Court Opinion

ID: 2738861
Source: CourtListenerOpinion
Date Created: 2014-10-01 17:00:46.387809+00
Date Added: 2024-06-11T12:41:06.639926
License: Public Domain

PRECEDENTIAL

      UNITED STATES COURT OF APPEALS
           FOR THE THIRD CIRCUIT
                _____________

                    No. 12-2548
                   _____________

          UNITED STATES OF AMERICA,
                           Appellant

                          v.

 HARRY KATZIN; MICHAEL KATZIN; MARK LOUIS
                KATZIN, SR.
               _____________

    On Appeal from the United States District Court
       for the Eastern District of Pennsylvania
          (D.C. Criminal No. 5:11-cr-00226)
     District Judge: Honorable Gene E.K. Pratter
                   _____________

              Argued on March 19, 2013
   Rehearing En Banc Ordered on December 12, 2013
            Argued En Banc May 28, 2014
                   _____________

Before: McKEE, Chief Judge, RENDELL, AMBRO,
FUENTES, SMITH, FISHER, CHAGARES, JORDAN,

                          1
HARDIMAN,     GREENAWAY,    JR.,     VANASKIE,
SHWARTZ, and VAN ANTWERPEN, Circuit Judges.

                  (Filed: October 1, 2014)
                      _____________

Robert A. Zauzmer, Esq. [ARGUED]
Emily McKillip, Esq.
Zane D. Memeger, Esq.
Thomas M. Zaleski, Esq.
Office of United States Attorney
615 Chestnut Street
Suite 1250
Philadelphia, PA 19106
       Counsel for Appellant United States of America

Catherine N. Crump, Esq. [ARGUED]
American Civil Liberties Union
125 Broad Street
18th Floor
New York, NY 10004

Thomas A. Dreyer, Esq.
Suite 110
6 Dickinson Drive
Building 100
Chadds Ford, PA 19317-0000
       Counsel for Appellee Harry Katzin

William A. DeStefano, Esq.
Stevens & Lee
1818 Market Street
29th Floor

                             2
Philadelphia, PA 19103
      Counsel for Appellee Michael Katzin

Rocco C. Cipparone, Jr., Esq.
205 Black Horse Pike
Haddon Heights, NJ 08035-0000
      Counsel for Appellee Mark Louis Katzin, Sr.

Brett G. Sweitzer, Esq.
Federal Community Defender Office for the Eastern District
of Pennsylvania
601 Walnut Street
The Curtis Center, Suite 540 West
Philadelphia, PA 19106
       Counsel for Amicus Appellee Federal Public &
   Community Defender Organization of the Third Circuit

Catherine N. Crump, Esq. [ARGUED]
Nathan Wessler, Esq.
American Civil Liberties Union
125 Broad Street
18th Floor
New York, NY 10004

Benjamin E. Wizner, Esq.
American Civil Liberties Union
National Security Project
125 Broad Street
18th Floor
New York, NY 10004
       Counsel for Amicus Appellee American Civil Liberties
       Union

                             3
Catherine N. Crump, Esq. [ARGUED]
American Civil Liberties Union
125 Broad Street
18th Floor
New York, NY 10004

Sara J. Rose, Esq.
Witold J. Walczak, Esq.
American Civil Liberties Union
313 Atwood Street
Pittsburgh, PA 15213
       Counsel for Amicus Appellee American Civil Liberties
       Union Foundation of Pennsylvania

Catherine N. Crump, Esq. [ARGUED]
American Civil Liberties Union
125 Broad Street
18th Floor
New York, NY 10004

Hanni M. Fakhoury, Esq.
Marcia Hoffman, Esq.
Electronic Frontier Foundation
815 Eddy Street
San Francisco, CA 94109
       Counsel for Amicus Appellee Electronic Frontier
       Foundation

Catherine N. Crump, Esq. [ARGUED]
American Civil Liberties Union
125 Broad Street
18th Floor
New York, NY 10004

                             4
Peter Goldberger, Esq.
50 Rittenhouse Place
Ardmore, PA 19003
       Counsel for Appellee National Association of Criminal
       Defense Lawyers
                       _____________

                OPINION OF THE COURT
                    _____________

VAN ANTWERPEN, Circuit Judge, with whom RENDELL,
FISHER, CHAGARES, JORDAN, HARDIMAN,
VANASKIE, and SHWARTZ, Circuit Judges, join.

        The instant appeal arises out of the warrantless
installation of a Global Positioning System device (a “GPS”
or “GPS device”) and subsequent surveillance by agents
working for the Federal Bureau of Investigation (“FBI”) of a
van while investigating multiple pharmacy burglaries. The
warrantless surveillance led to evidence of the involvement of
brothers Harry, Michael, and Mark Katzin (collectively,
“Appellees”) in the burglaries. Slightly more than a year after
the GPS installation and surveillance, the Supreme Court
decided United States v. Jones, which held that the
installation of a GPS device by government agents upon the
exterior of a vehicle and subsequent use of that device to
monitor the vehicle’s movements is a Fourth Amendment
“search.” 132 S. Ct. 945, 949 (2012). As a result, Appellees
successfully moved prior to trial to suppress the evidence
collected pursuant to the warrantless GPS surveillance,
effectively ending the Government’s prosecution. We
conclude that the evidence is admissible under the good faith

                              5
exception to the exclusionary rule and reverse the District
Court’s grant of Appellees’ suppression motions.

                   I.     BACKGROUND

       In 2009 and 2010, the FBI and local police officers
were investigating a series of pharmacy burglaries occurring
in the greater Philadelphia area, including Delaware,
Maryland, and New Jersey. The modus operandi was
consistent: the perpetrators, who targeted Rite Aid
pharmacies, disabled alarm systems by cutting the external
telephone lines.

       Eventually, Harry Katzin emerged as a suspect. A
local electrician, he had recently been arrested for attempting
to burglarize a Rite Aid pharmacy, and he and his brothers
had criminal histories involving arrests for burglary and theft.
Increasingly, investigators received reports of Harry Katzin’s
involvement in suspicious activities in the vicinity of Rite Aid
pharmacies.1 Their investigation revealed the make and

1
   For example, in October 2010 Pennsylvania police found
Harry Katzin crouching behind bushes near a Rite Aid. They
did not arrest him but the following day discovered the Rite
Aid’s phone lines had been cut. A month later, police
searched Harry Katzin’s van after discovering him and two
other individuals (including his brother Michael) sitting inside
it near a Rite Aid. Police found tools, work gloves, and ski
masks in the van but did not arrest the men. Again, police
later discovered the Rite Aid’s phone lines were cut. Finally,
that same month, surveillance camera footage from a
burglarized New Jersey Rite Aid showed a van similar to
Harry Katzin’s parked in its vicinity.

                               6
model of Harry Katzin’s van, as well as where he primarily
parked it, and the agents sought to electronically surveil him.
The agents conferred with an Assistant United States
Attorney (“AUSA”) who advised them, in conformity with
Department of Justice (“DOJ”) policy at the time, that
installing a battery-powered GPS device upon Harry Katzin’s
van on a public street and tracking its movements on public
thoroughfares would not require a warrant. Subsequently, on
December 13, 2010, without a warrant, officers magnetically
attached a battery powered “slap-on” GPS device2 onto the
undercarriage of Harry Katzin’s van while it was parked on a
public street.

       Two days later, at approximately 10:45 p.m. on
December 15, 2010, the GPS device indicated that Harry
Katzin’s van had left Philadelphia and proceeded on public
thoroughfares to the immediate vicinity of a Rite Aid in
Hamburg, Pennsylvania. According to the GPS device, the
van drove around the area before stopping and remaining
stationary for over two hours. The agents contacted local
police but instructed them to maintain a wide perimeter to
avoid alerting the suspects. Consequently, the GPS provided
the only evidence of the van’s proximity to the Rite Aid. The
van left its position at nearly 3:00 a.m. and state troopers

2
 A “slap-on” GPS device magnetically attaches to a vehicle’s
exterior and is battery powered, requiring no electrical
connection to the vehicle. It uses a network of satellites to
calculate its location and transmits the data to a central server.
An officer need not physically track nor be near the
automobile. The GPS that the agents used had a battery life of
one week (although the agents could have changed the
batteries, if necessary).

                                7
followed. Meanwhile, local police confirmed that someone
had burglarized the Rite Aid and relayed this information to
the troopers, who pulled over the van. Troopers found Harry
Katzin at the wheel with Michael and Mark as passengers.
From outside the van, troopers observed items consistent with
the burglary of a Rite Aid.3 They arrested Appellees and
impounded the van. In all, the warrantless GPS surveillance
lasted for two days and occurred only on public
thoroughfares.

       Appellees were indicted and each moved to suppress
the evidence recovered from the van. They argued that the
warrantless installation and monitoring of the GPS device
violated their Fourth Amendment rights pursuant to Jones.
The Government argued, inter alia, that even if Jones now
required a warrant, the evidence should not be suppressed
because the agents acted in good faith when installing and
monitoring the GPS device.

        The United States District Court for the Eastern
District of Pennsylvania granted Appellees’ suppression
motions. United States v. Katzin, No. 11-226, 2012 WL
1646894, at *11 (E.D. Pa. May 9, 2012). The District Court
found that a warrant was required under Jones. Id. at *5–6.
Relying on Davis v. United States, 131 S. Ct. 2419 (2011), it
also rejected the Government’s good faith argument, refusing
to “extend the good faith exception to encompass the conduct
in this case.” Id. at *10. Finally, it concluded that, contrary to
the Government’s contention, passengers Mark and Michael

3
  The state trooper saw merchandise, pill bottles, Rite Aid
storage bins, tools, a duffel bag, and a surveillance system
with severed wires.

                                8
Katzin had standing to challenge the search of Harry Katzin’s
van. Id. at *11. The Government appealed.

       A panel of this Court unanimously affirmed the
District Court’s conclusions that the agents’ conduct required
a warrant and that all three brothers had standing. United
States v. Katzin, 732 F.3d 187, 191 (3d Cir. 2013), vacated by
United States v. Katzin, No. 12-2548, 2013 WL 7033666 (3d
Cir. Dec. 12, 2013) (granting rehearing en banc). However,
the panel divided over whether the good faith exception
applied and, consequently, whether suppression was
appropriate. See id. at 216–41 (Van Antwerpen, J.,
dissenting). The Government petitioned for, and we granted,
rehearing en banc on the singular issue of whether the
evidence recovered from Harry Katzin’s van should be
shielded from suppression pursuant to the good faith
exception to the exclusionary rule. Katzin, 2013 WL
7033666, at *1. We conducted the en banc rehearing on May
28, 2014.

                   II.    DISCUSSION4

      The Fourth Amendment mandates that

4
  The District Court had jurisdiction pursuant to 18 U.S.C. §
3231. We have jurisdiction under 18 U.S.C. § 3731 and 28
U.S.C. § 1291. In reviewing a motion to suppress, “we review
a district court’s factual findings for clear error, and we
exercise de novo review over its application of the law to
those factual findings.” United States v. Pavulak, 700 F.3d
651, 660 (3d Cir. 2012).

                              9
       [t]he right of the people to be secure in their
       persons, houses, papers, and effects, against
       unreasonable searches and seizures, shall not be
       violated, and no Warrants shall issue, but upon
       probable cause, supported by Oath or
       affirmation, and particularly describing the
       place to be searched, and the persons or things
       to be seized.

U.S. Const. amend. IV. Accordingly, the Fourth Amendment
only prohibits “unreasonable” searches and seizures. Skinner
v. Ry. Labor Executives’ Ass’n, 489 U.S. 602, 619 (1989); see
also Vernonia Sch. Dist. 47J v. Acton, 515 U.S. 646, 652
(1995) (“[T]he ultimate measure of the constitutionality of a
governmental search is ‘reasonableness.’”). Searches
conducted absent a warrant are per se unreasonable under the
Fourth Amendment, subject to certain exceptions. United
States v. Harrison, 689 F.3d 301, 306 (3d Cir. 2012). To deter
Fourth Amendment violations, when the Government seeks to
admit evidence collected pursuant to an illegal search or
seizure, the judicially created doctrine known as the
exclusionary rule at times suppresses that evidence and makes
it unavailable at trial. Herring v. United States, 555 U.S. 135,
139 (2009). However, even when the Government violates
the Fourth Amendment, ill-gotten evidence will not be
suppressed when the good faith exception to the exclusionary
rule applies. See, e.g., United States v. Leon, 468 U.S. 897,
920–26 (1984) (refusing to exclude fruits of unreasonable
search because officer acted with objective good faith on later
invalidated warrant).

       Consequently, we need not determine whether the
agents’ conduct was an unreasonable search because, even

                              10
assuming so, we conclude that the good faith exception
applies, and that suppression is unwarranted.5 However, we
caution that, after Jones, law enforcement should carefully
consider that a warrant may be required when engaging in
such installation and surveillance. We also need not reach the
issue of whether Mark and Michael Katzin have standing to
challenge the agents’ conduct because, even assuming so, the
outcome—admission of the evidence at trial—would remain
unchanged.6 See United States v. Stearn, 597 F.3d 540, 553
(3d Cir. 2010) (noting that district court only needed to
determine “standing” to the extent it held searches
unreasonable); United States v. Varlack Ventures, Inc., 149
F.3d 212, 216 (3d Cir. 1998) (declining to decide standing
where court determined that law enforcement properly
conducted warrantless search). We nevertheless acknowledge
that, under the law of the Third Circuit, United States v.
Mosley, 454 F.3d 249 (3d Cir. 2006) appears to control.

      A.     The Exclusionary Rule and the Good Faith
             Exception

5
  This approach is consistent with that taken by our sister
circuits when addressing the installation and use of GPS or
GPS-like devices that occurred prior to Jones. See, e.g.,
United States v. Brown, 744 F.3d 474, 476 (7th Cir. 2014);
United States v. Aguiar, 737 F.3d 251, 255 (2d Cir. 2013);
United States v. Andres, 703 F.3d 828, 834 (5th Cir. 2013);
United States v. Pineda-Moreno, 688 F.3d 1087, 1090 (9th
Cir. 2012).
6
  We use the term “standing” as shorthand for determining
whether a litigant’s Fourth Amendment rights are implicated.
See United States v. Mosley, 454 F.3d 249, 253 n.5 (3d Cir.
2006).

                             11
        Whether to suppress evidence under the exclusionary
rule is a separate question from whether the Government has
violated an individual’s Fourth Amendment rights. Hudson v.
Michigan, 547 U.S. 586, 591–92 (2006). Despite its
connection to the Fourth Amendment, there is no
constitutional right to have the evidentiary fruits of an illegal
search or seizure suppressed at trial. See, e.g., Davis, 131 S.
Ct. at 2426 (noting that the Fourth Amendment “says nothing
about suppressing evidence obtained in violation of [its]
command”). The exclusionary rule is instead “a judicially
created means of effectuating the rights secured by the Fourth
Amendment.” Stone v. Powell, 428 U.S. 465, 482 (1976).
Simply because a Fourth Amendment violation occurs does
not mean that exclusion necessarily follows. E.g., Herring,
555 U.S. at 140. Rather, “exclusion ‘has always been our last
resort, not our first impulse.’” Id. (quoting Hudson, 547 U.S.
at 591).

        Application of the exclusionary rule is instead limited
to those “unusual cases” in which it may achieve its
objective: to appreciably deter governmental violations of the
Fourth Amendment. Leon, 468 U.S. at 909, 918; see also
United States v. Duka, 671 F.3d 329, 346 (3d Cir. 2011). To
the extent the promise of admitting illegally seized evidence
creates an incentive to disregard Fourth Amendment rights,
the exclusionary rule removes that incentive by “forbid[ding]
the use of improperly obtained evidence at trial.” Herring,
555 U.S. at 139. It thereby “compel[s] respect for the [Fourth
Amendment’s] constitutional guaranty.” Elkins v. United
States, 364 U.S. 206, 217 (1960).

      However, while “[r]eal deterrent value” is necessary
for the exclusionary rule to apply, there are other

                               12
considerations and it alone is not sufficient. Davis, 131 S. Ct.
at 2427. Deterrence must also outweigh the “substantial social
costs” of exclusion. Leon, 468 U.S. at 907. These costs often
include omitting “reliable, trustworthy evidence” of a
defendant’s guilt, thereby “suppress[ing] the truth and
set[ting] [a] criminal loose in the community without
punishment.” Davis, 131 S. Ct. at 2427. As this result
conflicts with the “truth-finding functions of judge and jury,”
United States v. Payner, 447 U.S. 727, 734 (1980), exclusion
is a “bitter pill,” Davis, 131 S. Ct. at 2427, swallowed only as
a “last resort,” Hudson, 547 U.S. at 591. Accordingly, to
warrant exclusion, the deterrent value of suppression must
overcome the resulting social costs. Davis, 131 S. Ct. at 2427.

       The good faith exception to the exclusionary rule was
developed to effectuate this balance and has been applied
“across a range of cases.”7 Id. at 2428. Where the particular
facts of a case indicate that law enforcement officers “act[ed]
with an objectively ‘reasonable good-faith belief’ that their
conduct [was] lawful, or when their conduct involve[d] only
simple, ‘isolated’ negligence,” there is no illicit conduct to
deter. Id. at 2427–28 (citations omitted) (quoting Leon, 468
U.S. at 909; Herring 555 U.S. at 137). In such circumstances,
“the deterrence rationale loses much of its force and exclusion

7
  See Davis, 131 S. Ct. at 2429 (applying good faith exception
where officers relied on binding appellate precedent);
Herring, 555 U.S. at 147–48 (same, with police-maintained
outstanding warrant database); Arizona v. Evans, 514 U.S. 1,
14–16 (1995) (same, with court-maintained database); Illinois
v. Krull, 480 U.S. 340, 349–50 (1987) (same, with
subsequently invalidated statute); Leon, 468 U.S. at 922
(same, with subsequently invalidated warrant).

                              13
cannot pay its way.” Id. at 2428 (quoting Leon, 468 U.S. at
907 n.6, 919) (internal quotation marks omitted).
Alternatively, where law enforcement conduct is “deliberate,
reckless, or grossly negligent” or involves “recurring or
systemic negligence,” deterrence holds greater value and
often outweighs the associated costs. Id. at 2427–28 (quoting
Herring, 555 U.S. at 144) (internal quotation marks omitted).
Put differently, exclusion is appropriate only where law
enforcement conduct is both “sufficiently deliberate” that
deterrence is effective and “sufficiently culpable” that
deterrence outweighs the costs of suppression. Herring, 555
U.S. at 144. Thus, determining whether the good faith
exception applies requires courts to answer the “objectively
ascertainable question whether a reasonably well trained
officer would have known that the search was illegal in light
of all of the circumstances.” Id. at 145 (quoting Leon, 468
U.S. at 922 n.23) (internal quotation marks omitted).

             1.     Davis v. United States

       In Davis, the Supreme Court applied the good faith
exception in the context of law enforcement officers’ reliance
on judicial decisions. 131 S. Ct. at 2423–24. Specifically,
Davis held that “searches conducted in objectively reasonable
reliance on binding appellate precedent are not subject to the
exclusionary rule.” Id. Davis’ holding implicated two prior
Supreme Court decisions, New York v. Belton, 453 U.S. 454
(1981) and Arizona v. Gant, 556 U.S. 332 (2009).

        In Belton, the Supreme Court announced a seemingly
broad and permissive standard regarding searches incident to
arrest. 453 U.S. at 460 (“[W]hen a policeman has made a
lawful custodial arrest of the occupant of an automobile, he

                             14
may, as a contemporaneous incident of that arrest, search the
passenger compartment of that automobile.” (footnote
omitted)). It was widely understood that the Court had issued
a bright-line rule, and that vehicle searches incident to the
arrest of recent occupants were reasonable, regardless of
whether the arrestee “was within reaching distance of the
vehicle at the time of the search.” Davis, 131 S. Ct. at 2424.
However, as Davis noted, the Supreme Court’s subsequent
decision in Gant upset this interpretation of Belton. Id. at
2425. After Gant, a vehicle search incident to a recent
occupant’s arrest was only constitutionally reasonable where
(1) “the arrestee [was] within reaching distance of the vehicle
during the search, or (2) . . . the police ha[d] reason to believe
that the vehicle contain[ed] ‘evidence relevant to the crime of
arrest.’” Id. (quoting Gant, 556 U.S. at 343).

       Before Gant, the Eleventh Circuit had been one of
many federal appeals courts to read Belton as establishing a
permissive rule. See United States v. Gonzalez, 71 F.3d 819,
822 (11th Cir. 1996) (upholding search of vehicle conducted
after recent occupant was “pulled from the vehicle,
handcuffed, laid on the ground, and placed under arrest”).
After Belton and Gonzalez, but before Gant, police officers in
a case arising in the Eleventh Circuit arrested both the driver
of a vehicle and the vehicle’s occupant, Willie Davis. 131 S.
Ct. at 2425. After handcuffing and placing them in the back
of separate patrol cars, officers searched the vehicle and
found a revolver in Davis’ jacket. Id. The District Court
denied Davis’ Fourth Amendment challenge, but during the
pendency of his appeal from his conviction for possession of
a firearm by a convicted felon, the Supreme Court decided
Gant. Id. at 2426. Accordingly, when Davis reached the
Supreme Court, it was necessary to address “whether to apply

                               15
the exclusionary rule when the police conduct a search in
objectively reasonable reliance on binding judicial
precedent,” such as Gonzalez. Id. at 2428.

        Crucial to Davis’ holding that suppression was not
warranted was the “acknowledged absence of police
culpability.” Id. The officers’ conduct was innocent because
they “followed the Eleventh Circuit’s Gonzalez precedent to
the letter” and conducted themselves “in strict compliance
with then-binding Circuit law.” Id. Because “well-trained
officers will and should use” a law enforcement tactic that
“binding appellate precedent specifically authorizes,”
evidence suppression would only serve to deter what had
been reasonable police work. Id. at 2429. As this outcome
was inimical to the exclusionary rule’s purpose, namely
deterrence, the Supreme Court applied the good faith
exception to the officers’ conduct, rendering suppression
inappropriate. Id. (“About all that exclusion would deter in
this case is conscientious police work.”).

       B.     The District Court’s Reliance on Davis

       In the case at bar, the District Court refused to “stray[]
from the limitations set forth in Davis and expand[] the good
faith exception.” Katzin, 2012 WL 1646894, at *9–10. It
viewed Davis as setting forth a requirement that there be
relevant binding precedent within the circuit. Id. at *7.
Because no binding Third Circuit precedent specifically
authorized the agents’ actions, it reasoned that applying the
good faith exception would involve “[e]xtending” the holding
of Davis from binding appellate precedent to an area of
unsettled law. Id. at *7, *9. Still, it acknowledged that “an
argument could be made . . . that the more general good faith

                               16
exception language” permits “individualized determination”
of whether law enforcement acted objectively reasonably in
specific cases. Id. at *9. It also “hasten[ed] to emphasize” its
lack of concern that the agents acted in a “calculated or
otherwise deliberately cavalier or casual manner in the hopes
of just meeting the outer limits of the constitutional contours
of [Appellees’] rights.” Id. at *10 n.15. It admitted that the
agents “could well profess surprise at the specific outcome of
Jones.” Id. Despite these conclusions, however, the District
Court refused “to move beyond the strict Davis holding,” and
it suppressed the evidence against Appellees.8 Id. at *9.
Appellees urge us to adopt the District Court’s interpretation
of Davis. They argue that no binding appellate precedent
under Davis existed upon which the agents could reasonably
rely, and they warn us to refrain from “fabricat[ing] a new
ground for application of the ‘good faith’ exception”: reliance
on a “settled body of persuasive authority.” (Appellees’
Corrected Supplemental En Banc Brief (“Appellee En Banc
Br.”) at 3–4.)

       C.     The agents acted in good faith under both Davis
              v. United States and the general good faith
              exception.

8
  The District Court relied on “policy issues” it believed
militated against “[e]xtending Davis” and applying the good
faith exception. Katzin, 2012 WL 1646894, at *9.
Specifically, it questioned the practicality of assigning
authoritative weight to out-of-circuit decisions, noted that the
good faith exception generally involved “reliance on
unequivocally binding legal authority,” and concluded that
reliance on out-of-circuit authority “at least border[ed] on
being categorized as systemic negligence.” Id.

                              17
        We disagree with the District Court in two respects.
First, we conclude that the exclusionary rule should not apply
because, at the time of the agents’ conduct in this case, the
Supreme Court’s decisions in United States v. Knotts, 460
U.S. 276 (1983) and United States v. Karo, 468 U.S. 705
(1984) were binding appellate precedent upon which the
agents could reasonably have relied under Davis. In the
alternative, we conclude that, under the Supreme Court’s
more general good faith test, the evidence should not be
suppressed because the agents acted with a good faith belief
in the lawfulness of their conduct that was “objectively
reasonable.” Davis, 131 S. Ct. at 2427.

              1.    Knotts and Karo were binding appellate
              precedent upon which the agents could
              reasonably have relied under Davis.

       As an initial matter, it is self-evident that Supreme
Court decisions are binding precedent in every circuit. See,
e.g., United States v. Aguiar, 737 F.3d 251, 260–61 (2d Cir.
2013) (rejecting contention that “binding appellate precedent”
must be in-circuit precedent). The question remains whether
the agents’ reliance on Knotts and Karo was “objectively
reasonable.” Davis, 131 S. Ct. at 2428. We believe it was.
Although the underlying facts in the cases differed—which
will nearly always be true—the rationale underpinning the
Supreme Court’s decisions in Knotts and Karo clearly
authorized the agents’ conduct.

       For a law enforcement officer’s conduct to fall under
the ambit of Davis, a court must answer in the affirmative that
he or she has “conduct[ed] a search [or seizure] in objectively
reasonable reliance on binding judicial precedent.” Id. If that

                              18
is the case, this “absence of police culpability dooms”
motions to suppress evidence gathered pursuant to an
allegedly illegal search or seizure. Id. The concept of
“objectively reasonable reliance” for good faith purposes has
been in practice since long before Davis was decided and
requires answering “whether a reasonably well trained officer
would have known that [a] search was illegal . . . . [under] all
of the circumstances . . . .” Leon, 468 U.S. at 922 n.23; see
also Herring, 555 U.S. at 142 (noting that case law often
refers to “objectively reasonable reliance” as “good faith”).
The “circumstance” at the forefront of Davis’ analysis is the
existence of binding appellate precedent, and the dispositive
inquiry is whether reliance upon it is “objectively
reasonable.” Davis, 131 S. Ct. at 2428.

        As a threshold matter, we note that our inquiry is two-
fold. The agents magnetically attached a battery-operated
GPS onto the undercarriage of Harry Katzin’s van and
tracked its movements for two days. Jones analyzed this kind
of conduct as a singular act. 132 S. Ct. at 949 (installation of
GPS and its use to track vehicle are a search). However, prior
to Jones, GPS or GPS-like surveillance was, for Fourth
Amendment purposes, often treated as two distinct acts: (1)
installation of the surveillance device, and (2) use of the
device to track suspects’ movements. See, e.g., Karo, 468
U.S. at 711–13 (analyzing Fourth Amendment implications of
beeper installation); id. at 713–18 (analyzing Fourth
Amendment implications of beeper surveillance); Knotts, 460
U.S. at 279 n.** (granting certiorari on Fourth Amendment
implications of beeper use, but passing on installation);
United States v. Pineda-Moreno, 591 F.3d 1212, 1215–16
(9th Cir. 2010) (analyzing GPS installation separately from
use), vacated, 132 S. Ct. 1533 (2012), remanded to 688 F.3d
19
1087 (9th Cir. 2012). Accordingly, we analyze the
reasonableness of the agents’ reliance upon binding appellate
precedent under Davis with respect to both of these Fourth
Amendment acts.

       It was objectively reasonable for the agents to rely
upon Karo in concluding that the warrantless installation of
the GPS device was legal. In Karo, an agent with the Drug
Enforcement Agency (“DEA”) learned that James Karo and
others had ordered, for use in cocaine smuggling, fifty gallons
of ether from a government informant. 468 U.S. at 708. With
the informant’s consent, the Government substituted one of
the informant’s cans of ether with its own can, which
contained a beeper. Id. Karo picked up the ether and took the
“bugged” can into his car. Id. For over four months, DEA
agents intermittently monitored the beeper to determine the
location of the can. Id. at 708–10. The Government had
obtained a court order authorizing this conduct, but it was
subsequently invalidated, and, on appeal, the Government did
not challenge its invalidation. Id. at 708, 710. Thus, when the
case reached the Supreme Court, it presented the question
whether the beeper’s warrantless installation was legal. Id. at
711.

        The Supreme Court affirmed the warrantless
installation of the beeper, holding that it infringed no Fourth
Amendment rights. Id. at 713. It reasoned that the transfer to
Karo of the can containing the unmonitored beeper was not a
search because the transfer conveyed no information, and
therefore infringed no privacy interest. Id. at 712. Nor was the
transfer a seizure despite the “technical trespass on the space
occupied by the beeper,” which the Court admitted was an
“unknown and unwanted foreign object.” Id. In so holding,

                              20
the Court broadly discredited the relevance of trespass in the
context of electronic surveillance of vehicles: “[A] physical
trespass is only marginally relevant to the question of whether
the Fourth Amendment has been violated, . . . for an actual
trespass is neither necessary nor sufficient to establish a
constitutional violation.” Id. at 712–13.

       The magnetic attachment of an unmonitored GPS unit
onto the exterior of Harry Katzin’s vehicle, like the mere
transfer of a can containing an unmonitored beeper, did not
convey any information. It would have been objectively
reasonable for a law enforcement officer to conclude, prior to
Jones and in reliance on Karo, that such conduct was not a
search because it infringed no privacy interest. The same
result applies to the “trespass” of the GPS device (also an
“unknown and unwanted foreign object”) upon Harry
Katzin’s vehicle. It would have been objectively reasonable
for a law enforcement officer to conclude that Karo’s
sweeping rejection of the trespass theory applied not only the
DEA agents’ elaborate ruse therein, but also to the
unremarkable strategy of magnetically attaching a battery-
operated GPS unit onto the exterior of a vehicle. In sum,
although the facts of this case differ from Karo’s, the
Supreme Court’s rationale was broad enough to embrace the
agents’ conduct, and their reliance on this binding appellate
precedent was objectively reasonable under Davis.

       It was also objectively reasonable for the agents to rely
upon Knotts and Karo in concluding that the warrantless
monitoring of the GPS device was legal. In Knotts, like Karo,
law enforcement arranged for a suspect to voluntarily take
into his vehicle a container that, unbeknownst to him,
contained a beeper. 460 U.S. at 278. The police thereby

                              21
monitored his travels on public roads. Id. The Supreme Court
rejected the defendant’s Fourth Amendment challenge to the
surveillance, holding that “[a] person travelling in an
automobile on public thoroughfares has no reasonable
expectation of privacy in his movements from one place to
another.” Id. at 281; see also Karo, 468 U.S. at 713–16, 721
(reaffirming Knotts but clarifying that monitoring beeper
inside private residence violates Fourth Amendment due to
reasonable expectation of privacy enjoyed therein). This is so
because a traveler on public streets “voluntarily convey[s]” to
any observer the “particular roads” over which he travels, his
“particular direction,” any stops he makes, and his “final
destination.” 460 U.S. at 281–82. The Government’s
surveillance “amounted principally” to legal conduct:
physically following a suspect on public roads. Id. at 281. The
beeper’s use changed little because “[n]othing in the Fourth
Amendment prohibited the police from augmenting [their]
sensory faculties . . . with such enhancement as science and
technology afforded them in this case.” Id. at 282.

        With respect to surveillance, the agents here engaged
in nearly identical conduct to that authorized in Knotts.
Appellees “voluntarily conveyed” their travels over public
roads and the information gathered by the GPS device was
indistinguishable from that which physical surveillance would
have revealed. See id. at 281–82. Again, the breadth of the
Supreme Court’s rationale in Knotts and Karo encompasses
the agents’ conduct, and we conclude that reliance upon this
binding appellate precedent was objectively reasonable under
Davis. In so concluding, we join a number of our sister
circuits in deciding that, for the purposes of the good faith
inquiry as applied to these facts, the technological distinctions
between the beepers of yesteryear and the GPS device used

                               22
herein are irrelevant. See Aguiar, 737 F.3d at 255, 261
(deciding that beeper used in Knotts was “sufficiently
similar” to GPS device employed for approximately six
months); United States v. Sparks, 711 F.3d 58, 66 (1st Cir.
2013) (concluding that “Knotts clearly authorized” law
enforcement’s use, for eleven days, of GPS device instead of
beeper); see also United States v. Fisher, 745 F.3d 200, 205
(6th Cir. 2014) (concluding that in-circuit beeper cases were
binding appellate precedent for “sporadic[]” GPS use); United
States v. Andres, 703 F.3d 828, 835 (5th Cir. 2013) (same, for
approximately two-day use).

       We acknowledge, of course, that these cases are not
factually identical to the agents’ conduct. The agents
monitored Harry Katzin’s van for two days by GPS, not
beeper. They clandestinely installed a battery-operated GPS
by magnetically attaching it onto the undercarriage of his van
rather than clandestinely tricking him into unwittingly taking
the GPS device into his vehicle. Otherwise their conduct
echoed that in Knotts and Karo. No two cases will be
factually identical. While the underlying facts of the cases are
obviously relevant to determining whether reliance is
objectively reasonable, the question is not answered simply
by mechanically comparing the facts of cases and tallying
their similarities and differences. Rather, Davis’ inquiry
involves a holistic examination of whether a reasonable
officer would believe in good faith that binding appellate
precedent authorized certain conduct, which is a scenario-
specific way of asking the broader question of whether the
officer “act[ed] with an objectively ‘reasonable good-faith
belief’ that [his] conduct [was] lawful.” Davis, 131 S. Ct. at
2427 (quoting Leon, 468 U.S. at 909).

                              23
        Undoubtedly, certain language in Davis invites a
narrow reading, but we are not persuaded this interpretation is
true to Davis’ holding. For instance, Davis found exclusion
inappropriate where “binding appellate precedent specifically
authorize[d] a particular police practice.” Id. at 2429. We
construe, arguendo, this language narrowly to mean that the
relied-upon case must affirmatively authorize the precise
conduct at issue in the case under consideration. Stated as a
syllogism, if binding appellate precedent specifically
authorizes the precise conduct under consideration, then it
will likely be binding appellate precedent upon which police
can reasonably rely under Davis. However, this does not
make the reverse syllogism true, namely, that if a case is
binding appellate precedent under Davis, then it must
specifically authorize the precise conduct under
consideration. Davis’ holding is broader: “[e]vidence
obtained during a search conducted in reasonable reliance on
binding precedent is not subject to the exclusionary rule.” Id.
While reliance is likely reasonable when the precise conduct
under consideration has been affirmatively authorized by
binding appellate precedent, it may be no less reasonable
when the conduct under consideration clearly falls well
within rationale espoused in binding appellate precedent,
which authorizes nearly identical conduct.

       Accordingly, what is far more important to our
conclusion is that, despite these few dissimilarities, the
agents’ nearly identical conduct fits squarely within the
rationale of these decisions. We, therefore, believe that, at the
time of the conduct at issue here, Knotts and Karo were
binding appellate precedent, which could reasonably be relied
on, under Davis. At least one other circuit has held so and
explicitly rejected the contention that binding appellate

                               24
precedent must be “(1) within the Circuit and (2) specific to
the facts at hand.” Aguiar, 737 F.3d at 260–61 (holding that,
before Jones, Knotts and Karo were binding appellate
precedent under Davis for purposes of GPS installation and
surveillance of a vehicle on public roads); see also United
States v. Brown, 744 F.3d 474, 478 (7th Cir. 2014) (Knotts
and Karo are binding appellate precedent for purposes of
consensual GPS installation and subsequent surveillance).

         2.   Suppression is inappropriate because the
agents        acted under an objectively reasonable good
faith         belief that their conduct was lawful.

              a.     The alleged inapplicability of Davis does
              not control the issue.

        Alternatively, even if we were to accept Appellees’
argument that factual dissimilarities disqualify Knotts and
Karo from being “binding appellate precedent” which could
reasonably be relied on under Davis, our inquiry would not
end there. In advancing their contrary position, the District
Court and Appellees improperly elevate Davis’ holding above
the general good faith analysis from whence it came. Davis is
but one application of the good faith exception that applies
when police “conduct a search in objectively reasonable
reliance on binding judicial precedent.” Davis, 131 S. Ct. at
2428. Undoubtedly, Davis is the most analogous Supreme
Court decision to the instant circumstances. However, even if
Davis did not mandate the application of the good faith
exception, we can still apply the exception for another good
reason. Cf. United States v. Knights, 534 U.S. 112, 117 (2001)
(rejecting the “dubious logic . . . that an opinion upholding
the constitutionality of a particular search implicitly holds

                             25
unconstitutional any search that is not like it”). The whole of
our task is not to determine whether Davis applies, nor to
“extend” either the good faith exception or Davis’ holding.
Even where Davis does not control, it is our duty to consider
the totality of the circumstances to answer the “objectively
ascertainable question whether a reasonably well trained
officer would have known that the search was illegal.”9 Leon,
468 U.S. at 906–07, 922 n.23 (noting that exclusion inquiries
“must be resolved by weighing the costs and benefits of
[suppression]” (emphasis added)). To exclude evidence
simply because law enforcement fell short of relying on
binding appellate precedent would impermissibly exceed the
Supreme Court’s mandate that suppression should occur in
only “unusual” circumstances: when it “further[s] the

9
  The District Court noted that the Supreme Court’s good
faith decisions generally involved reliance on some
“unequivocally binding” authority, which does not include
non-binding case law. Katzin, 2012 WL 1646894, at *9; see
also supra note 7. However, in the Supreme Court’s many
enunciations of the governing standard, it has never made
such authority a condition precedent to applying the good
faith exception. See, e.g., Herring, 555 U.S. at 137 (noting
that suppression “turns on the culpability of the police and the
potential of exclusion to deter wrongful police conduct”);
Evans, 514 U.S. at 13–14 (suppression appropriate “only if
the remedial objectives of the rule are thought most
efficaciously served”); Leon, 468 U.S. at 918 (good faith
exception requires “objectively reasonable belief that . . .
conduct did not violate the Fourth Amendment”). We do no
more than apply the good faith exception as articulated by the
Supreme Court.

                              26
purposes of the exclusionary rule.” Id. at 918; see also Duka,
671 F.3d at 346.

        Davis supports this conclusion. In reaching its holding,
Davis reiterates the analytical steps for evaluating suppression
challenges. 131 S. Ct. at 2426–28. For example, we must
limit operation of the exclusionary rule “to situations in which
[its] purpose,” deterring future Fourth Amendment violations,
is “most efficaciously served.” Id. at 2426 (quoting United
States v. Calandra, 414 U.S. 338, 348 (1974)). Our analysis
must account for both “[r]eal deterrent value” and
“substantial social costs,” and our inquiry must focus on the
“flagrancy of the police misconduct” at issue. Id. at 2427
(quoting Leon, 468 U.S. at 907, 911). Only when, after a
“rigorous weighing,” we conclude that “the deterrence
benefits of suppression . . . outweigh its heavy costs,” is
exclusion appropriate. Id. Importantly, we must be prepared
to “appl[y] this ‘good-faith’ exception across a range of
cases.”10 Id. at 2428.

10
   Moreover, we note that Justice Sotomayor understood
Davis explicitly to leave open the question “whether the
exclusionary rule applies when the law governing the
constitutionality of a particular search is unsettled.” Davis,
131 S. Ct. at 2435 (Sotomayor, J., concurring). Similarly,
Justice Breyer did not read Davis to limit the good faith
exception only to “binding appellate precedent.” Id. at 2439
(Breyer, J., dissenting) (arguing that culpability rationale
could similarly excuse as good faith a search which an officer
“believes complies with the Constitution but which . . . falls
just outside the Fourth Amendment’s bounds [or] where
circuit precedent is simply suggestive rather than ‘binding,’

                              27
       Davis did not begin, nor end, with binding appellate
precedent. Rather, binding appellate precedent informed—
and ultimately determined—the Supreme Court’s greater
inquiry: whether the officers’ conduct was deliberate and
culpable enough that application of the exclusionary rule
would “yield meaningfu[l] deterrence,” and “be worth the
price paid by the justice system.” Id. at 2428 (alteration in
original) (quoting Herring, 555 U.S. at 144) (internal
quotation marks omitted). We must conduct the same analysis
on the facts before us, even in the absence of binding
appellate precedent.11

       The District Court acknowledged the argument that the
“general good faith exception language” could permit an
“individualized determination” of whether the agents’

where it only describes how to treat roughly analogous
instances, or where it just does not exist”).
11
   Appellees’ warning not to “fabricate” a new good faith
ground exemplifies this misreading of Davis. (Appellee En
Banc Br. at 4.) The Davis Court did not “fabricate” binding
appellate precedent as a ground for applying the good faith
exception. The facts involved binding appellate precedent, but
the ground for applying the good faith exception was—as it
has been since Leon—that the deterrence rationale was
unsatisfied. Davis, 131 S. Ct. at 2428–29 (noting the
“absence of police culpability” and that excluding evidence
would deter only “objectively reasonable law enforcement
activity” (quoting Leon, 468 U.S. at 919)). The factual
circumstances before us differ, but we ground our application
of the good faith exception in the same time-tested
considerations.

                             28
conduct was objectively reasonable. Katzin, 2012 WL
1646894, at *8. This determination would have been properly
informed by its conclusion that the agents’ inadvertent Fourth
Amendment violation was neither “calculated” nor the result
of a “deliberately cavalier or casual” attitude toward
Appellees’ Fourth Amendment rights, and that the agents
were likely “surprise[d]” by Jones.” Id. at *10 n.15; see also
Davis, 131 S. Ct. at 2429 (noting that the Supreme Court has
“‘never applied’ the exclusionary rule to suppress evidence
obtained as a result of nonculpable, innocent police conduct”
(quoting Herring, 555 U.S. at 144)). However, the District
Court declined to apply the good faith exception on the theory
that doing so would implicate or “extend” the “strict Davis
holding.” Id. at *9–10. This conclusion prevented the District
Court from answering, as was its duty, the “objectively
ascertainable question whether a reasonably well trained
officer would have known that the search was illegal . . . .
[under] all of the circumstances . . . .” Leon, 468 U.S. at 922
n.23.

                    b.     The Legal Landscape

       In applying the good faith exception analysis to the
agents’ conduct, we initially address the precise conduct at
issue and the legal landscape at the time the agents acted. The
agents magnetically attached a battery-operated GPS onto the
undercarriage of Harry Katzin’s van and tracked its
movements for two days. As noted above, we analyze the
reasonableness of the agents’ conduct as would a pre-Jones
court, namely, by separately considering installation and
surveillance. E.g., Karo, 468 U.S. at 711–18.

                              29
       Application of the good faith exception turns on
whether the agents, at the time they acted, would have or
should have known their installation of the GPS and their
subsequent monitoring of Harry Katzin’s vehicle were
unconstitutional. See Krull, 480 U.S. at 348–49. Relevant to
this determination are the Supreme Court’s case law dealing
with electronic surveillance and general searches of
automobiles, subsequent treatment of GPS or GPS-like
surveillance across the federal courts, and other
considerations.

                           i.        Knotts and Karo

        Until Katz v. United States, 389 U.S. 347 (1967), the
Supreme Court’s primary Fourth Amendment inquiry was
whether the Government committed a physical trespass. See,
e.g., id. at 352 (noting that the absence of trespass was once
“thought to foreclose further Fourth Amendment inquiry”).
Katz changed this, famously declaring that “the Fourth
Amendment protects people, not places.” Id. at 351, 353
(“[T]he reach of [the Fourth] Amendment cannot turn upon
the presence or absence of a physical intrusion . . . . [T]he
‘trespass’ doctrine . . . can no longer be regarded as
controlling.”). Subsequently, Katz was widely regarded as
having jettisoned reliance on physical trespass in resolving
Fourth Amendment challenges. See, e.g., United States v.
Santillo, 507 F.2d 629, 632 (3d Cir. 1975) (noting that the
“trespassory concepts” relied upon in earlier Fourth
Amendment cases have been “discredited”). After Katz, the
dominant Fourth Amendment inquiry became whether the
Government had intruded upon a person’s reasonable
expectation of privacy. See Katz, 389 U.S. at 360 (Harlan, J.,
concurring); see also, e.g., Rakas v. Illinois, 439 U.S. 128,

                                30
143 (1978) (noting that one’s “capacity” to invoke Fourth
Amendment protections depends upon whether one has a
legitimate expectation of privacy, not a property right, in the
invaded place).

        In Knotts and Karo, the Supreme Court applied this
rationale to electronic surveillance of vehicles. We
incorporate our earlier discussion of these cases, pausing only
to reiterate Knotts’ conclusion that “[a] person travelling in an
automobile on public thoroughfares has no reasonable
expectation of privacy in his movements from one place to
another,” 460 U.S. at 281, as well as Karo’s broad rejection
of the trespass theory in the context of electronic surveillance
of vehicles: “[A] physical trespass is only marginally relevant
to the question of whether the Fourth Amendment has been
violated, . . . for an actual trespass is neither necessary nor
sufficient to establish a constitutional violation.” 468 U.S. at
712–13.

        Also relevant to the installation question are the
Supreme Court’s conclusions that persons do not enjoy a
reasonable expectation of privacy in the exterior of their
vehicles. New York v. Class, 475 U.S. 106, 114 (1986) (“The
exterior of a car, of course, is thrust into the public eye, and
thus to examine it does not constitute a ‘search.’”); Cardwell
v. Lewis, 417 U.S. 583, 591–92 (1974) (plurality opinion) (no
privacy interest infringed where search examined tire on
wheel and took paint scrapings from exterior of vehicle in
public parking lot).

       Thus, at bottom, before Jones, Knotts and Karo
established that no Fourth Amendment search occurred where
officers used beeper-based electronics to monitor an

                               31
automobile’s movements on public roads because a person
has no reasonable expectation of privacy with regard to that
information. Additionally, the rationale they espoused
informed the federal appeals courts’ subsequent treatment of
direct installation of a GPS device onto the exterior of a
vehicle.

                            ii.        Out-of-Circuit Decisions

       After Knotts and Karo, what resulted was a nearly
uniform consensus across the federal courts of appeals that
addressed the issue that the installation and subsequent use of
a GPS or GPS-like device was not a search, or, at most, was a
search but did not require a warrant. See, e.g., United States v.
Marquez, 605 F.3d 604, 609–10 (8th Cir. 2010) (reasoning
that GPS installation and use requires only reasonable
suspicion, since monitoring on public roads is not a search);
Pineda-Moreno, 591 F.3d at 1215–16 (holding that mobile
tracking device installation and use was not a search); United
States v. Garcia, 474 F.3d 994, 997 (7th Cir. 2007) (holding
that GPS installation and use was not a search), abrogation
recognized by United States v. Brown, 744 F.3d 474 (7th Cir.
2014); United States v. McIver, 186 F.3d 1119, 1126–27 (9th
Cir. 1999) (holding that GPS installation was not a search);
see also United States v. Michael, 645 F.2d 252, 256–58 (5th
Cir. 1981) (en banc) (holding that beeper installation and use
requires only reasonable suspicion, since monitoring on
public roads is not a search).12

12
   Michael was also Eleventh Circuit law. See Bonner v. City
of Prichard, 661 F.2d 1206, 1209 (11th Cir. 1981) (en banc)
(Fifth Circuit decisions before October 1, 1981 bind Eleventh
Circuit). Michael was decided May 11, 1981. 645 F.2d at 252.

                                  32
       The lone dissenting voice was United States v.
Maynard, 615 F.3d 544 (D.C. Cir. 2010), decided four
months prior to the agents’ conduct here. Maynard (which
became Jones on appeal to the Supreme Court) held that
prolonged GPS surveillance of a vehicle “24 hours a day for
four weeks” was a Fourth Amendment search because it
invaded the defendant’s reasonable expectation of privacy. Id.
at 555. The D.C. Circuit reasoned that Knotts held only that a
person travelling by vehicle on public roads had no
reasonable expectation of privacy in his movements, not that
“such a person has no reasonable expectation of privacy in his
movements whatsoever, world without end.” Id. at 557.
Maynard thus focused on the quality and quantity of
information gathered during the extended surveillance. Id. at
562 (noting that prolonged surveillance, unlike short-term
surveillance, exposes “what a person does repeatedly, what he
does not do, and what he does ensemble,” thereby revealing
more information than an isolated trip). It reasoned that the
defendant’s movements were “not actually exposed to the
public because the likelihood a stranger would observe all
those movements is not just remote, it is essentially nil.” Id. at
560.

       Thus, at the time the agents acted, in addition to the
“beeper” authority of Knotts and Karo, three circuit courts
expressly approved their use of a GPS or GPS-like device,
and the lone dissenting voice involved surveillance of a far
longer duration.

                             iii.    AUSA Consultation

                                33
        Finally, the agents consulted with, and received
approval from, an AUSA on their proposed conduct. It was
DOJ policy at the time that a warrant was not required to
install a battery-powered GPS on a vehicle parked on a public
street and to surveil it on public roads. We have previously
considered reliance on government attorneys in our good faith
calculus and concluded that, based upon it in combination
with other factors, “[a] reasonable officer would . . . have
confidence in [a search’s] validity.”13 United States v. Tracey,
597 F.3d 140, 153 (3d Cir. 2010); see also United States v.
Fama, 758 F.2d 834, 837 (2d Cir. 1985) (same).

        Jones fundamentally altered this legal landscape by
reviving—after a forty-five year hibernation—the Supreme
Court’s prior trespass theory. 132 S. Ct. at 952 (declaring that
reasonable expectation of privacy inquiry did not substitute
for “common-law trespassory test”). As the Ninth Circuit
recently stated: “The agents in Jones labored under the
misconception that the ‘reasonable expectation of privacy’
test exclusively marked the [Fourth] Amendment’s
boundaries. Cases fostering that impression were ubiquitous.”
United States v. Thomas, 726 F.3d 1086, 1094 n.8 (9th Cir.
2013) (citation omitted) (citing numerous Supreme Court
cases).

13
   At oral argument before the original panel, counsel for
Appellee Mark Katzin conceded that we may properly
consider the AUSA consultation in the totality of
circumstances informing our good faith analysis. Transcript
of Oral Argument at 52, United States v. Katzin, 732 F.3d 187
(3d Cir. 2013), vacated by United States v. Katzin, No. 12-
2548, 2013 WL 7033666 (3d Cir. Dec. 12, 2013) (No. 12-
2548).

                              34
       With this legal landscape in mind, we turn now to our
application of the good faith exception to the exclusionary
rule.

                     c.    Applying      the    Good      Faith
                     Exception

       To reiterate, the exclusionary rule is a prudential
doctrine designed solely to deter future Fourth Amendment
violations. Davis, 131 S. Ct. at 2426. Marginal deterrence is,
however, insufficient for suppression; rather, deterrence must
be “appreciable,” Leon, 468 U.S. at 909, and outweigh the
heavy social costs of suppressing reliable, probative evidence,
Davis, 131 S. Ct. at 2427. This balancing act pivots upon the
fulcrum of the “flagrancy of the police misconduct” at issue.
Id. (quoting Leon, 468 U.S. at 911). Thus, “[w]hen the police
exhibit deliberate, reckless, or grossly negligent disregard for
Fourth Amendment rights, the deterrent value of exclusion is
strong and tends to outweigh the resulting costs.” Id. (quoting
Herring, 555 U.S. at 144) (internal quotation marks omitted).
However, “when the police act with an objectively reasonable
good-faith belief that their conduct is lawful . . . the
deterrence rationale loses much of its force and exclusion
cannot pay its way.” Id. at 2427–28 (quoting Leon, 468 U.S.
at 907 n.6, 909, 919) (internal quotation marks omitted).

       Accordingly, we must determine whether—on these
particular facts—the agents acted with a good faith belief in
the lawfulness of their conduct that was “objectively
reasonable.” Id. If so, suppression is unwarranted. If, on the
other hand, the agents “had knowledge, or may properly be
charged with knowledge, that the search was unconstitutional

                              35
under the Fourth Amendment,” suppression is warranted.
Krull, 480 U.S. at 348–49. When answering these questions,
we consider “all of the circumstances” and confine our
inquiry to the “objectively ascertainable question whether a
reasonably well trained officer would have known that the
search was illegal” in light of that constellation of
circumstances. Leon, 468 U.S. at 922 n.23.

        We conclude that when the agents acted, they did so
upon an objectively reasonable good faith belief in the
legality of their conduct, and that the good faith exception to
the exclusionary rule therefore applies. The constellation of
circumstances that appeared to authorize their conduct
included well settled principles of Fourth Amendment law as
articulated by the Supreme Court, a near-unanimity of circuit
courts applying these principles to the same conduct, and the
advice of an AUSA pursuant to a DOJ-wide policy. Given
this panoply of authority, we cannot say that a “reasonably
well trained officer would have known that the search was
illegal,” id., nor that the agents acted with “deliberate,
reckless, or grossly negligent disregard for [Appellees’]
Fourth Amendment rights,” Davis, 131 S. Ct. at 2427
(quoting Herring, 555 U.S. at 144) (internal quotation marks
omitted). Thus, suppression is inappropriate because it would
not result in deterrence appreciable enough to outweigh the
significant social costs of suppressing reliable, probative
evidence, upon which the Government’s entire case against
Appellees turns. See Leon, 468 U.S. at 909.

                           i.        Knotts and Karo

      Knotts and Karo are seminal cases on the intersection
of electronic surveillance of vehicles and the Fourth

                                36
Amendment. Before Jones, their conclusion that the Fourth
Amendment was not implicated by the installation and use of
a beeper to surveil vehicles on public thoroughfares, and the
rationale that supported it, was hornbook law. See, e.g.,
Aguiar, 737 F.3d at 261 (“Karo’s brushing off of the potential
trespass fits logically with earlier Supreme Court decisions
concluding that ‘the physical characteristics of an automobile
and its use result in a lessened expectation of privacy
therein.’” (quoting Class, 475 U.S. at 112)); Sparks, 711 F.3d
at 67 (“Knotts was widely and reasonably understood to stand
for the proposition that the Fourth Amendment simply was
not implicated by electronic surveillance of public automotive
movements . . . .”). The agents would have been objectively
reasonable to conclude that monitoring Harry Katzin’s van
was constitutional, in large part, because it fell squarely
within Knotts and Karo’s well-accepted rationale. Their
targets were “person[s] travelling in an automobile on public
thoroughfares,” who had “no reasonable expectation of
privacy in [their] movements from one place to another.”
Knotts, 460 U.S. at 281. It is undisputed that Appellees
“voluntarily convey[ed]” to any observer the “particular
roads” over which they traveled, their “particular direction,”
their stops, and their “final destination.” Id. at 281–82. At no
time did the GPS permit the agents to monitor inside “a
private residence” or other area “not open to visual
surveillance.” Karo, 468 U.S. at 714, 721.

       Additionally, the agents would have been objectively
reasonable to believe that installing the GPS device
implicated no Fourth Amendment rights. The Supreme Court
had repeatedly stated that persons do not enjoy a reasonable
expectation of privacy in the exterior of their vehicles. Class,
475 U.S. at 114; see also Cardwell, 417 U.S. at 591. It was

                              37
also objectively reasonable for the agents to believe that
installing a GPS was safe from a trespass challenge. Katz
clearly stated that Fourth Amendment inquiries did not “turn
upon the presence or absence of a physical intrusion.” 389
U.S. at 353. The trespass doctrine had been “discredited.”
Santillo, 507 F.2d at 632.

       The agents also benefitted from Supreme Court
precedent addressing trespass in the context of electronic
surveillance of vehicles on public roads. Although Karo did
not address direct installation, its renunciation of the trespass
theory was broad enough for agents reasonably to conclude
that the installation was “only marginally relevant” to
Appellees’ Fourth Amendment rights and alone was “neither
necessary nor sufficient to establish a constitutional
violation.” 468 U.S. at 712–13. They could have reasonably
believed that the only constitutionally significant act they
engaged in was monitoring. Id. at 713 (rejecting trespass
theory and noting that privacy violation, if any, was
“occasioned by the monitoring of the beeper”). And, as
discussed, the agents had no reason to believe the monitoring
was illegal.

                            ii.        Out-of-Circuit Decisions

       The agents’ conduct also conformed to practices
authorized by a “uniform treatment” of “continuous judicial
approval” of warrantless GPS installation and use across the
federal courts. See Peltier, 422 U.S. at 540–42 & n.8 (holding
exclusionary rule inapplicable where illegal search was
conducted in good faith reliance on, in part, holdings and

                                  38
dicta of various courts of appeals).14 Specifically, when the
agents acted, the Seventh,15 Eighth,16 and Ninth17 Circuits had
all held that the installation of GPS or GPS-like devices upon
the exterior of vehicles and their subsequent monitoring either
was not a search or, at most, was a search but did not require
a warrant.18 Their rationales were based on the same Supreme
Court precedents we outline above, particularly Knotts.

14
    Although Peltier was applying the “old retroactivity
regime” of Linkletter v. Walker, 381 U.S. 618 (1965), Leon
“explicitly relied on Peltier and imported its reasoning into
the good-faith inquiry.” Davis, 131 S. Ct. at 2431–32.
15
   Garcia, 474 F.3d at 997–98.
16
   Marquez, 605 F.3d at 609–10.
17
   Pineda-Moreno, 591 F.3d at 1215–17; McIver, 186 F.3d at
1126–27.
18
   The D.C. Circuit in Maynard broke from this consensus
and held that prolonged GPS surveillance of the defendant’s
vehicle “24 hours a day for four weeks” was a Fourth
Amendment search. 615 F.3d at 555. The D.C. Circuit
explicitly tailored its holding to the fact that surveillance of
the defendant lasted for a month. Id. at 558, 560 (“Applying
the foregoing analysis to the present facts, we hold the whole
of a person’s movements over the course of a month is not
actually exposed to the public . . . .”). It also relied
exclusively on a reasonable expectation of privacy rationale,
giving no hint at Jones’ revival of the trespass theory. Id. at
559–61. We cannot conclude that from this sole departure
from the consensus of the courts of appeals “a reasonably
well trained officer would [or should] have known” that the
more limited GPS surveillance in this case was illegal. Leon,
468 U.S. at 922 n.23.

                              39
       By considering these non-binding decisions in our
good faith analysis, we do no more than did the Supreme
Court in Peltier. There, the Court considered the
“constitutional norm” established by the courts of appeals
when determining whether an officer “had knowledge, or
[could] properly be charged with knowledge, that [a] search
was unconstitutional under the Fourth Amendment.” Id. at
542 (“[U]nless we are to hold that parties may not reasonably
rely upon any legal pronouncement emanating from sources
other than this Court, we cannot regard as blameworthy those
parties who conform their conduct to the prevailing . . .
constitutional norm.”).19

                            iii.    AUSA Consultation

       Finally, the agents’ consultation with the AUSA also
supports our conclusion that a reasonable agent would have
believed in good faith that the installation and surveillance of
Harry Katzin’s vehicle was legal. Of course, the AUSA
approved their conduct. But more importantly, the AUSA’s
advice was given pursuant to a DOJ-wide policy—
presumably based upon the legal landscape we describe
above—that the agents’ conduct did not require a warrant.

19
   This Court has also previously noted—albeit in limited
ways—supportive out-of-circuit decisions in its good faith
analyses. See, Pavulak, 700 F.3d at 664 (holding that officer
relied in good faith upon warrant and noting that “the
affidavit’s allegations would have been sufficient in the
Eighth Circuit at the time”); Duka, 671 F.3d at 347 n.12
(concluding that objective reasonableness of reliance on
statute was “bolstered” by out-of-circuit decisions reviewing
particular provision and declaring it constitutional).

                               40
Prosecutors are, of course, not “neutral judicial officers.”
Leon, 468 U.S. at 917. We do not place undue weight on this
factor, but we have previously considered it in our good faith
analysis. Tracey, 597 F.3d at 153; see also United States v.
Otero, 563 F.3d 1127, 1134–35 (10th Cir. 2009).

        In light of the aforementioned legal landscape, when
the agents installed the GPS device onto the undercarriage of
Harry Katzin’s vehicle, and then used that device to monitor
his vehicle’s movements on public thoroughfares for two
days, we believe those agents exhibited “an objectively
‘reasonable good-faith belief’ that their conduct [was]
lawful.” Davis, 131 S. Ct. at 2427 (quoting Leon, 468 U.S. at
909). Given the panoply of authority authorizing their actions,
we cannot conclude that a “reasonably well trained officer
would have known that the search was illegal,” Leon, 468
U.S. at 922 n.23, nor that the agents acted with a “deliberate,
reckless, or grossly negligent disregard for [Appellees’]
Fourth Amendment rights,” Davis, 131 S. Ct. at 2427
(quoting Herring, 555 U.S. at 144) (internal quotation marks
omitted). Prior to Jones’ unforeseeable revival of the
“discredited” trespass theory, Santillo, 507 F.2d at 632, a
reasonable police officer would have concluded that the
agents’ conduct did not require a warrant. Suppression in this
case would only deter “conscientious police work.” Id. at
2429. Accordingly, suppression of the evidence discovered as
a result of the agents’ conduct would not “outweigh the
resulting costs,” and “exclusion cannot ‘pay its way.’” Id. at
2427–28 (quoting Leon, 468 U.S. at 907 n.6).20

20
  Our sister circuits’ complementary conclusions support this
result. See Brown, 744 F.3d at 478 (Knotts and Karo are
binding appellate precedent for purposes of consensual GPS

                              41
                     d.     Appellees’ Arguments

       Appellees argue that excluding the evidence against
them would achieve appreciable deterrence because it would
prevent investigators and prosecutors from “engaging in
overly aggressive readings of non-binding authority” and
deter law enforcement from “‘act[ing] in a constitutionally

installation and subsequent surveillance); Aguiar, 737 F.3d at
261 (same, for purposes of nonconsensual installation and
subsequent surveillance); Sparks, 711 F.3d at 67 (Knotts is
binding appellate precedent where police install GPS and
surveil vehicle’s movements). Although the Seventh Circuit
left open the question of nonconsensual GPS installation, it
strongly suggested that applying the good faith exception
would be appropriate based upon out-of-circuit authority.
Brown, 744 F.3d at 478 (doubting deterrent effect of
prohibiting police from relying on out-of-circuit authority
“just because the circuit . . . lacks its own precedent”). We
also note that the First Circuit did not clearly distinguish
where its reliance on Knotts ended and reliance on its own
precedent began. See Sparks, 711 F.3d at 67 (relying on both
Knotts and United States v. Moore, 562 F.2d 106 (1st Cir.
1977), abrogation recognized by United States v. Oladosu,
744 F.3d 36 (1st Cir. 2014)). However, it relied on Knotts for
the same reasons we highlight. See id. at 66–67 (declaring
that Knotts was “widely and reasonably understood” to mean
electronic surveillance of vehicles on public roads did not
implicate Fourth Amendment and that it “clearly authorized”
use of GPS in place of beeper). Finally, as noted earlier, our
sister circuits have routinely concluded, as we do on these
facts, that there is no relevant distinction between beepers and
GPS devices for good faith purposes.

                              42
reckless fashion’ by taking constitutional inquiries into their
own hands.” (Appellee En Banc Br. at 5 (quoting Katzin, 732
F.3d at 212).) To so hold would lead to the same result as the
District Court’s erroneous application of Davis: the good faith
exception would not apply unless our own Court had
established binding appellate precedent directly on point and
approving the officer’s conduct. Put differently, all innocently
(though later deemed illegally) gathered evidence would be
excluded unless the police conduct discovering it was
expressly permitted at the time the conduct occurred. But the
purpose of the exclusionary rule is to deter “wrongful police
conduct.” Herring, 555 U.S. at 137. And exclusion is only
appropriate when doing so “most efficaciously serve[s]” that
purpose. Calandra, 414 U.S. at 348. The mere act of deciding
that conduct is lawful based upon a “constitutional norm”
rather than binding appellate precedent is unlike the highly
culpable conduct that helped establish the exclusionary rule.
See, e.g., Herring, 555 U.S. at 143 (listing cases and noting
that “the abuses that gave rise to the exclusionary rule
featured    intentional    conduct     that    was      patently
unconstitutional”).

       No doubt, sometimes officers’ reliance on non-binding
authorities will fall short of an “objectively reasonable” good
faith belief in the legality of their conduct. Suppression may
then be appropriate to deter such reliance. It is equally
elementary that close cases will be difficult.21 But in many

21
   We are unpersuaded by Appellees’ warning that our
holding will require a “complicated judgment about whether
non-binding case law is sufficiently ‘settled’ and
‘persuasive.’” (Appellee En Banc Br. at 6.) The Fourth
Amendment routinely requires courts to make difficult

                              43
other cases, law enforcement will likely correctly conclude,
based upon a panoply of non-binding authority establishing a
“constitutional norm,” Peltier, 422 U.S. at 542, that a
particular police practice does not violate the Fourth
Amendment. The value in deterring such conduct is low.
Additionally, adopting such a bright-line rule may
impermissibly avoid our duty to conduct in each case a
“rigorous weighing” of suppression’s costs and benefits,
Davis, 131 S. Ct. at 2427, and to consider “all of the
circumstances” to determine the “objectively ascertainable
question whether a reasonably well trained officer would
have known that the search was illegal,” Leon, 468 U.S. at
922 n.23. We would also risk “generat[ing] disrespect for the
law and administration of justice” by applying the
exclusionary rule so indiscriminately. Id. at 908 (quoting
Stone, 428 U.S. at 491).

       Because such a bright-line rule would supplant the
required balancing act, we would have to be confident that in
every conceivable future case, the substantial costs of
suppression would be outweighed by the value of deterring
police from relying on a “constitutional norm” simply
because it had yet to be expressly established by precedential
opinion in the Third Circuit. We have no such confidence and
Appellees do little to assuage our concerns. Appellees’ good
faith calculus conspicuously fails to confront the “cost” side
of the equation, which they dismiss as “minimal.” (Appellee
En Banc Br. at 8.) However, the Supreme Court has routinely

determinations of reasonableness. See, e.g., Scott v. Harris,
550 U.S. 372, 383 (2007) (noting that the Fourth Amendment
requires courts to “slosh . . . through the factbound morass of
‘reasonableness’”).

                              44
stated the opposite; the cost of suppression is “substantial,”
Leon, 468 U.S. at 907, because it often excludes “reliable,
trustworthy evidence” of a defendant’s guilt, “suppress[es]
the truth and set[s] [a] criminal loose in the community
without punishment,” Davis, 131 S. Ct. at 2427. Here, by all
appearances, the Government’s evidence against Appellees is
substantial, and it is uncontested that the Government would
have no case without it. The costs of exclusion are high.

       The boundaries of the good faith exception are a
sufficient deterrent to the conduct Appellees find
objectionable. Law enforcement personnel will either tread
cautiously or risk suppression.22 The legal authority relied
upon must support an “objectively reasonable good faith
belief” that specific conduct is constitutional. Id. (quoting
Leon, 468 U.S. at 909) (internal quotation mark omitted).
Consequently, nothing in our holding today conflicts with the
Supreme Court’s instructions to executive officers to “err on

22
   As the Supreme Court noted in Leon, “the possibility that
illegally obtained evidence may be admitted in borderline
cases is unlikely to encourage police instructors to pay less
attention to fourth amendment limitations. . . . [nor]
encourage officers to pay less attention to what they are
taught, as the requirement that the officer act in ‘good faith’ is
inconsistent with closing one’s mind to the possibility of
illegality.” 468 U.S. at 919 n.20 (quoting Jerold Israel,
Criminal Procedure, the Burger Court, and the Legacy of the
Warren Court, 75 Mich. L. Rev. 1319, 1412–13 (1977)). The
Supreme Court has also recognized the “increasing evidence
that police forces across the United States take the
constitutional rights of citizens seriously.” Hudson, 547 U.S.
at 599.

                               45
the side of constitutional behavior,” United States v. Johnson,
457 U.S. 537, 561 (1982), and in “doubtful or marginal
case[s]” to obtain a warrant, Leon, 468 U.S. at 914 (quoting
United States v. Ventresca, 380 U.S. 102, 106 (1965)). We do
not believe this case to be either doubtful or marginal.23

        In any event, just because law enforcement officers
may one day unreasonably rely on non-binding authority does
not absolve us of our duty to decide whether, under these
facts, the agents’ conduct was “sufficiently deliberate” that
deterrence will be effective and “sufficiently culpable” that
deterrence outweighs the costs of suppression. Herring, 555
U.S. at 144. In this case neither standard is satisfied. Future
decisions may reveal that applying the good faith exception to
reliance on non-binding authority should be extremely rare,
perhaps as rare as tectonic shifts in Fourth Amendment
jurisprudence such as Jones. See Davis, 131 S. Ct. at 2433
(noting the infrequency with which the Supreme Court
overrules its Fourth Amendment precedents). But that is a
question for another day.
                   III. CONCLUSION

       For the foregoing reasons, we reverse the order of the
District Court suppressing the evidence discovered in Harry

23
   Appellees also argue that, under our holding, courts will
“defer to ‘adjuncts of the law enforcement team’ on the
difficult question of whether a particular legal issue is the
subject of ‘settled’ and ‘persuasive’ law.” (Appellee En Banc
Br. at 7.) The good faith analysis is not deferential. That
courts may be required to consider whether reliance on non-
binding authority is objectively reasonable does not change
the governing inquiry.

                              46
Katzin’s van and remand for further proceedings consistent
with this opinion.

                           47
GREENAWAY, JR., Circuit Judge, dissenting, joined by
McKEE, Chief Judge, and AMBRO, FUENTES, and SMITH,
Circuit Judges.

        Once touted as a way to ensure that the rights of
citizens are protected from overzealous law enforcement,
today the exclusionary rule’s very existence, long eroding, is
in serious doubt. Since the inception of the exclusionary rule,
critics have disputed its validity. In words often quoted, [then
Judge] Cardozo questioned whether “[t]he criminal is to go
free because the constable has blundered.” People v. Defore,
150 N.E. 585, 587 (N.Y. 1926). Courts have given power to
the words of the critics by using the good faith exception to
chip away at the breadth of the rule. The majority, in its
alternative holding, expands the good faith exception to the
point of eviscerating the exclusionary rule altogether by
failing to provide any cognizable limiting principle. Now,
law enforcement shall be further emboldened knowing that
the good faith exception will extricate officers from nearly
any evidentiary conundrum.

     Law    enforcement    violated    Katzin’s  Fourth
                 1
Amendment rights. In this case, the only means by which

1
  That the GPS placed on Katzin’s vehicle violated his Fourth
Amendment rights was not argued before the Third Circuit en
banc, as argument was restricted to the question of the
applicability of good faith. Before a good faith analysis can
proceed, there must first be a finding that a Fourth
Amendment violation occurred. The majority downplays the
significance of this requirement, noting that “we need not
determine whether the agents’ conduct was an unreasonable
search because, even assuming so, we conclude that the good
faith exception applies . . . .” Majority Op. at 10-11.

                               1
the evidence obtained through such a violation could be used
against Katzin is through application of the good faith
exception. To achieve this end, the majority argues that good
faith applies, even without the existence of binding appellate
precedent. What law enforcement did in this case was to
“rely on precedent to resolve legal questions as to which
‘[r]easonable minds . . . may differ . . . .’” United States v.
Davis, 598 F.3d 1259, 1267 (11th Cir. 2010), aff’d, 131 S. Ct.
2419 (2011) (quoting United States v. Leon, 468 U.S. 897,
914 (1984)). In such an instance, “the exclusionary rule is
well-tailored to hold [law enforcement] accountable for their
mistakes.” Id. The majority disagrees with this proposition
and instead gives free rein to law enforcement to interpret
legal propositions without any consequence if and when they
are wrong.

       Law enforcement contends that they acted reasonably
by consulting with their co-investigators at the U.S.
Attorney’s Office. However, what is missing here is neutral
authorization of any sort for the conduct undertaken by the
police. Consultation with the U.S. Attorney’s Office is not a
panacea for the constitutional issues raised here. Katz v.
United States, 389 U.S. 347, 356 (1967) (“It is apparent that

However, simultaneously, the majority notes that “[a] panel
of this Court unanimously affirmed the District Court’s
conclusions that the agents’ conduct required a warrant and
that all three brothers had standing.” Majority Op. at 9.
Here, the agents’ conduct constituted an unreasonable search,
and this finding is a predicate to any good faith analysis.
See, e.g., Davis v. United States, 131 S. Ct. 2419, 2428-29
(2011) (acknowledging the constitutional violation before
proceeding to the good faith analysis).

                              2
the agents in this case acted with restraint. Yet the
inescapable fact is that this restraint was imposed by the
agents themselves, not by a judicial officer. They were not
required, before commencing the search, to present their
estimate of probable cause for detached scrutiny by a neutral
magistrate. They were not compelled, during the conduct of
the search itself, to observe precise limits established in
advance by a specific court order. Nor were they directed,
after the search had been completed, to notify the authorizing
magistrate in detail of all that had been seized.”) (emphasis
added). Even if the majority believes that this neutral
authorization requirement (which admittedly pre-dates the
good faith exception) has been undercut by subsequent
Supreme Court decisions, we are still required to follow it.
Rodriguez de Quijas v. Shearson/Am. Express, Inc., 490 U.S.
477, 484 (1989) (“If a precedent of this Court has direct
application in a case, yet appears to rest on reasons rejected in
some other line of decisions, the Court of Appeals should
follow the case which directly controls, leaving to this Court
the prerogative of overruling its own decisions.”). Neutral
authorization for law enforcement’s actions has been the
hallmark of the good faith exception’s application. Without
this control, what is the fail-safe to preclude further erosion?
I fear there is none. For these reasons, I respectfully dissent.

       In its primary holding, the majority turns the rationale
of Davis on its head and concludes that two disparate
Supreme Court precedents—that the Government concedes
do not constitute binding appellate precedent—now fit the
bill.2 How does the majority justify the creation of such a

2
  At oral argument, the Government stated that its position
regarding United States v. Knotts, 460 U.S. 276 (1983) and

                               3
notion? Such a leap constitutes willful disregard of the
critical distinctions between this case on the one hand and
United States v. Knotts, 460 U.S. 276 (1983) and United
States v. Karo, 468 U.S. 705 (1984) on the other. Further,
this leap reveals the majority’s true purpose: to accommodate
the desires of law enforcement.

I. Expansion of the Good Faith Exception

       The majority’s alternative holding, that good faith
should apply even if it does not fit the Davis paradigm, is
troubling. The essence of the majority’s holding is that any
time a course of conduct by the police, particularly regarding
technological advancements, has not been tested or breaks
new ground, law enforcement will be entitled to the good
faith exception. 3 This directly contravenes one of the
principles expounded in Davis: that evidence admitted
pursuant to the good faith exception is so admitted because
the police relied on binding appellate precedent that, as
Justice Alito said in his majority opinion, “specifically
authorize[d the] particular police practice . . . .” Davis, 131
S. Ct. at 2429 (emphasis added). Indeed, as Justice
Sotomayor noted in her concurrence, Davis did not “present

United States v. Karo, 468 U.S. 705 (1984) is, “about one hair
short of [binding appellate precedent].” Tr. of Oral Argument
at 6, United States v. Katzin, ̶ F.3d ̶ (3d Cir. 2014) (en banc)
(No. 12-2548).
3
 At oral argument, the Government acknowledged that it was
asking for an expansion of the good faith exception, to which,
with today’s ruling, the majority has clearly acquiesced. Id.
at 23.

                               4
the markedly different question whether the exclusionary rule
applies when the law governing the constitutionality of a
particular search is unsettled.” Id. at 2435 (Sotomayor, J.,
concurring).4

       I do not dispute the majority’s contention that “Davis
is but one application of the good faith exception that applies
when police ‘conduct a search in objectively reasonable
reliance on binding judicial precedent.’” Majority Op. at 25
(quoting Davis, 131 S. Ct. at 2428). Instead, my point goes to
the manner in which the good faith exception is being
expanded. It has everything to do with neutral authorization
and with the ultimate decision-making not being in the hands
of law enforcement. This is what the framers envisioned

4
  The Eleventh Circuit’s opinion in Davis was also explicit on
this point: “[We refuse] to apply the exclusionary rule when
the police have reasonably relied on clear and well-settled
precedent. We stress, however, that our precedent on a given
point must be unequivocal before we will suspend the
exclusionary rule’s operation.” Davis, 598 F.3d at 1266
(citations omitted) (emphasis added); see also United States v.
Buford, 632 F.3d 264, 276 n.9 (6th Cir. 2011) (“Like the
Eleventh Circuit, we also ‘stress, however, that our precedent
on a given point must be unequivocal before we will suspend
the exclusionary rule’s operation.’” (quoting Davis, 598 F.3d
at 1266)); United States v. McCane, 573 F.3d 1037, 1045 n.6
(10th Cir. 2009) (finding that the good faith exception applied
because “Tenth Circuit jurisprudence supporting the search
was settled. Thus, there was no risk that law enforcement
officers would engage in the type of complex legal research
and analysis better left to the judiciary and members of the
bar”).

                              5
when they wrote the Fourth Amendment requiring that “no
Warrants shall issue, but upon probable cause, supported by
Oath or affirmation, and particularly describing the place to
be searched, and the persons or things to be seized.” U.S.
Const. amend. IV.

        Historically, the Supreme Court has held the good faith
exception covers situations where law enforcement personnel
have acted in objectively reasonable reliance on some
seemingly immutable authority or information that justifies
their course of action. See, e.g., United States v. Leon, 468
U.S. 897 (1984) (later-invalidated warrant); Massachusetts v.
Sheppard, 468 U.S. 981, 990 (1984) (exclusionary rule
inapplicable when warrant is invalid due to judicial clerical
error); Illinois v. Krull, 480 U.S. 340 (1987) (subsequently
overturned statute); Davis, 131 S. Ct. 2419 (later-reversed
binding appellate precedent); Arizona v. Evans, 514 U.S. 1
(1995) (undiscovered error in court-maintained database);
Herring v. United States, 555 U.S. 135 (2009) (undiscovered
error in police-maintained database).

       It is clear from the line of good faith cases that the
exception is limited to cases involving either: (a) non-
deterrable, isolated mistakes, or (b) cases in which police
officers rely upon a neutral third-party’s authorization.5 Such
delineated exceptions allow us to hold fast to the
constitutional guarantee of “[t]he right of the people to be
secure in their persons, houses, papers, and effects, against
unreasonable searches and seizures . . . .” U.S. Const. amend.
IV. Thus, “[i]t remains a cardinal principle that searches

5
  I limit my discussion to scenario (b) based on the facts of
this case.

                              6
conducted outside the judicial process, without prior approval
by judge or magistrate, are per se unreasonable under the
Fourth Amendment—subject only to a few specifically
established and well-delineated exceptions.” United States v.
Harrison, 689 F.3d 301, 306 (3d Cir. 2012) (internal
quotation marks omitted). The majority’s opinion, absent
such a guiding principle, has now leant its imprimatur to the
notion that even if law enforcement’s conduct violates the
Fourth Amendment, it is perfectly fine because the evidence
can come in through good faith. The exception becomes the
rule.

        The majority argues that the purpose of the
exclusionary rule is to deter wrongful conduct of law
enforcement, and that here there is no wrongful conduct. As
the Supreme Court has explained, “police conduct must be
sufficiently deliberate that exclusion can meaningfully deter
it, and sufficiently culpable that such deterrence is worth the
price paid by the justice system.” Herring, 555 U.S. at 144;
Davis, 131 S. Ct. at 2429 (cautioning courts not to discourage
“the officer from doing his duty”) (alteration and internal
quotation marks omitted). The majority determines that
acting on a good-faith mistake about the law, without seeking
a warrant even when there was time to get one, is not conduct
which should be deterred. But Davis itself suggests that it is
proper for the exclusionary rule to “punish” such an “error.”
Davis, 131 S. Ct. at 2428.

       Here, law enforcement personnel made a deliberate
decision to forego securing a warrant before attaching a GPS
device directly to a target vehicle in the absence of binding
Fourth Amendment precedent authorizing such a practice.
Indeed, the police embarked on a long-term surveillance
project using technology that allowed them to monitor a

                              7
target vehicle’s movements using only a laptop, all before
either this Circuit or the Supreme Court had spoken on the
constitutional propriety of such an endeavor. In an area
without any guidance from the Supreme Court or from our
Circuit, law enforcement and the prosecutors looked to our
sister circuits to find the universe of case law that supported
the most beneficial position to them. For purposes of our
analysis, we may not assume that Knotts and Karo were
binding appellate precedent simply because that is what law
enforcement, with assistance from the U.S. Attorney’s Office,
concluded at the time of their decision to place the GPS on
Katzin’s van. Thus, law enforcement made a deliberate
decision implicating constitutional principles on the basis of a
3-1 circuit split, absent any specific authorization for their
conduct. What if the split had been 2-2 or 1-3? Is there a
basis from which one can imagine that law enforcement’s
decision would have been different?

        True, the police did not act in a total vacuum, but their
chosen course of action when presented with such a novel
constitutional predicament is nonetheless worrisome. In lieu
of a binding proclamation from either this Circuit or the
Supreme Court—and instead of seeking approval from a
neutral magistrate—law enforcement personnel looked to
other (non-binding or distinguishable) authorities like our
sister circuits’ decisions. Essentially, they extrapolated their
own constitutional rule, in consultation with the U.S.
Attorney’s Office, and applied it to this case. This intra-
executive agency consultation falls short of a basic
requirement of the Fourth Amendment: that “where practical,
a governmental search and seizure should represent both the
efforts of the officer to gather evidence of wrongful acts and
the judgment of the magistrate that the collected evidence is

                               8
sufficient to justify invasion of a citizen’s private premises or
conversation.” United States v. U.S. District Court (Keith),
407 U.S. 297, 316 (1972). Simply put, the police in this case
dodged a basic constitutional separation of powers
requirement by choosing to assume a constitutional rule not
clearly established by binding judicial precedent.

       I do not believe that this intra-executive consultation
absolves police personnel’s behavior. Now, the assumption
by law enforcement that their own self-derived rule
sanctioned their conduct becomes true, thanks to the
majority’s analysis. Such decision-making is wrongful
conduct that can and should be deterred—for that is the
primary purpose of the exclusionary rule! The police practice
at issue here effectively disregarded the possibility that we
could find a GPS search constitutes a Fourth Amendment
violation requiring a warrant.

       Where we have not yet ruled on the constitutionality of
a police tactic, law enforcement personnel have two choices:
(a) assume that their conduct violates the Fourth Amendment
and that we will require them to obtain a warrant, or (b)
gamble, at the risk of having evidence excluded, that we will
find no Fourth Amendment violation in a particular situation.
This is in line with the Supreme Court’s suggestion that law
enforcement officials should be incentivized to “err on the
side of constitutional behavior.” United States v. Johnson,
457 U.S. 537, 561 (1982). 6 Excluding the evidence in this

6
   Johnson addressed retroactive application of Fourth
Amendment decisions. In discussing the matter, the Court
stated:

                               9
case would incentivize just that and would therefore result in
“appreciable deterrence” of future Fourth Amendment
violations. Leon, 468 U.S. at 909 (internal quotation marks
omitted).

       I would not hold, of course, that the police can never
make assumptions about our future Fourth Amendment
rulings. If their analysis is correct and we ultimately affirm
the constitutionality of a search, then the police are rewarded
with full use of any evidence derived from the search. If their
analysis is wrong, however, and the search is ultimately held
to be unconstitutional, then the police cannot avoid the cost of

       If, as the Government argues, all rulings
       resolving unsettled Fourth Amendment
       questions should be nonretroactive, then, in
       close cases, law enforcement officials would
       have little incentive to err on the side of
       constitutional behavior. Official awareness of
       the dubious constitutionality of a practice would
       be counterbalanced by official certainty that, so
       long as the Fourth Amendment law in the area
       remained unsettled, evidence obtained through
       the questionable practice would be excluded
       only in the one case definitively resolving the
       unsettled question. Failure to accord any
       retroactive effect to Fourth Amendment rulings
       would encourage police or other courts to
       disregard the plain purport of our decisions and
       to adopt a let’s-wait-until-it’s-decided approach.

Johnson, 457 U.S. at 561 (footnote and internal quotation
marks omitted).

                              10
suppression by relying on the good faith exception. Of
course, the police can avoid this entire issue by requesting a
warrant in the first instance, a task unburdened by time nor
trouble.

        Law enforcement personnel can rightly rely on a
number of sources for Fourth Amendment guidance—
including relevant decisions by the Supreme Court and this
Circuit, warrants, and statutes. We, both as a court and as a
society, expect that law enforcement officers will consult
these sources—it is a part of how we expect reasonable
officers to act. Davis, 131 S. Ct. at 2429. Deterring such
activity, therefore, would not serve the purposes of the
exclusionary rule. Id. This case is different. Nothing in a
law enforcement officer’s duties forces him either to rely on
non-binding appellate precedent or to conduct the Fourth
Amendment calculus himself by extrapolating from, or
analogizing to, existing case law. Where an officer decides to
take the Fourth Amendment inquiry into his own hands,
rather than to seek a warrant from a neutral magistrate—
particularly where the law is as far from settled as it was
here—he acts in a constitutionally reckless fashion.

       The legal landscape in this case predominantly
consisted of the out-of-circuit GPS cases, the Supreme
Court’s beeper decisions, and the overarching privacy
expectation framework for Fourth Amendment analysis
adopted in Katz and deemed to be the sole rubric for analysis
until United States v. Jones, 132 S. Ct. 945 (2012). Taken
together, the majority contends, these sources provide the
legal authority that would lead a reasonable law enforcement
officer to conclude that he was acting within the confines of
the Constitution when attaching a GPS tracker to the
undercarriage of Harry Katzin’s van. I do not agree that this

                             11
collection of authority warrants application of the good faith
exception because I remain discomfited by the lack of binding
appellate guidance or other neutral authorization underlying
the police action at issue here. Therefore, I would hold that
the police acted with sufficient constitutional culpability to
require exclusion and, more importantly, that suppression in
this case would help deter future Fourth Amendment
violations.

       My intention would not be to bind the hands of law
enforcement. I merely believe that the investigatory process
established by the Constitution is the proper one: that police
officers get a warrant prior to conducting a search. This is
also consistent with Karo, where the Court expressly rejected
the Government’s argument that requiring a warrant prior to
beeper tracking would be too laborious and would
substantially impede investigations. See Karo, 468 U.S. at
717 (“The Government’s contention that warrantless beeper
searches should be deemed reasonable is based upon its
deprecation of the benefits and exaggeration of the difficulties
associated with procurement of a warrant. The Government
argues that the traditional justifications for the warrant
requirement are inapplicable in beeper cases, but to a large
extent that argument is based upon the contention, rejected
above, that the beeper constitutes only a minuscule intrusion
on protected privacy interests . . . . Requiring a warrant will
have the salutary effect of ensuring that use of beepers is not
abused, by imposing upon agents the requirement that they
demonstrate in advance their justification for the desired
search.”) (emphasis added).

       Thus, I conclude that in the absence of binding
appellate precedent from the Supreme Court or this Court,
law enforcement must—as it has been required to do since the

                              12
founding of this country—comply with the warrant
requirement of the Fourth Amendment. This is clear and easy
to follow. This rule gives police officers not only sufficient
discretion, but also sufficient guidance to achieve their
objectives.

II. Why Knotts and Karo Do Not Constitute Binding
Appellate Precedent

       The majority elects to make an alternative holding:
that Knotts and Karo are binding appellate precedent. 7 I
disagree.

       Knotts and Karo stand for two propositions, only one
of which the majority has elected to acknowledge. First, in
Knotts the Supreme Court held that “[a] person traveling in an
automobile on public thoroughfares [generally] has no
reasonable expectation of privacy in his movements from one
place to another.” Knotts, 460 U.S. at 281. Second, the
Supreme Court stated that there remained the possibility that
twenty-four hour, “dragnet type law enforcement practices”
could implicate “different constitutional principles.” Id. at
283-84.

      The Supreme Court portended the exact case we have
before us now.     The Court astutely foretold that

7
  While the Supreme Court has leant its imprimatur to
alternative holdings, see, e.g., MacDonald, Sommer & Frates
v. Yolo Cnty., 477 U.S. 340, 346 n.4 (1986), in this instance I
believe that the use of an alternative holding emphasizes the
majority’s dubious faith in their argument that Knotts and
Karo constitute binding appellate precedent.

                              13
improvements in technology that would permit twenty-four
hour surveillance (i.e., GPS) might indeed present “different
constitutional principles.” Id. And now that this case is
before us, the majority ignores this second, critical takeaway
from Knotts and misrepresents that it constitutes binding
appellate precedent for purposes of permitting a Davis-based
good faith exception ruling.

       In addition to Knotts’ warning about “dragnet type law
enforcement practices,” discussed in more detail below, there
are three additional reasons why Knotts and Karo are not
binding appellate precedent, contrary to the majority’s
insistence: (1) the marked technological differences between
beepers and GPS trackers, (2) the placement by police of the
beepers inside containers with the consent of the owners in
those cases, and (3) the uncertainty in this area of law created
by the D.C. Circuit decision, United States v. Maynard, 615
F.3d 544 (D.C. Cir. 2010), which preceded the application of
the GPS device to the Katzin vehicle.

Technological Differences

       Our case concerns a “slap-on” GPS tracker, so called
because it magnetically attaches to the exterior of a target
vehicle, is battery operated, and thereby requires no electronic
connection to the automobile. The tracker uses the Global
Positioning System—a network of satellites originally
developed by the military—to determine its own location
with a high degree of specificity and then sends this data to a
central server. This check-and-report process repeats every
few minutes (depending on the tracker), thereby generating a
highly accurate record of the tracker’s whereabouts
throughout its period of operation. The great benefit of such
a system—apart from its accuracy—is that anyone with

                              14
access to the central server can analyze or monitor the
location data remotely. These aspects make GPS trackers
particularly appealing in law enforcement contexts, where the
police can attach a tracker to some vehicle or other asset and
then remotely monitor its location and movement.

       GPS technology is vastly different from the more
primitive tracking devices of yesteryear—“beepers.” Beepers
are nothing more than “radio transmitter[s], usually battery
operated, which emit[] periodic signals that can be picked up
by a radio receiver.” Knotts, 460 U.S. at 277. In contrast to
GPS trackers, beepers do not independently ascertain their
location—they only broadcast a signal that the police can then
follow via a corresponding receiver. Moreover, beeper
signals are range-limited: if the police move far enough away
from the beeper, they will be unable to receive the signal that
the unit broadcasts. At bottom, then, beepers are mere aids
for police officers already performing surveillance of a target
vehicle. Unlike GPS trackers, beepers require that the police
expend resources—time and manpower—to follow a target
vehicle physically.

       In a Ninth Circuit denial of a petition for rehearing on
the GPS question, Chief Judge Kozinski issued a fiery dissent
from the denial, accusing the Pineda-Moreno majority of
being “inclined to refuse nothing” to the needs of law
enforcement. United States v. Pineda-Moreno, 617 F.3d
1120, 1121 (9th Cir. 2010) (Kozinski, C.J., dissenting). In his
dissent, the Chief Judge noted that GPS devices “have little in
common with the primitive devices in Knotts,” in part
because, unlike GPS devices, beepers “still require[] at least
one officer—and usually many more—to follow the suspect.”
Id. at 1124. Thus, the dissent noted, while “[y]ou can
preserve your anonymity from prying eyes, even in public, by

                              15
traveling at night, through heavy traffic, in crowds, by using a
circuitous route, disguising your appearance, passing in and
out of buildings and being careful not to be followed,” there
is “no hiding from the all-seeing network of GPS satellites
that hover overhead, which never sleep, never blink, never get
confused and never lose attention.” Id. at 1126.

        As noted above, the Knotts Court specifically indicated
that, in contrast to the officers’ limited use of the beeper in
that case, more expansive monitoring, (e.g., a “twenty-four
hour,” “dragnet type law enforcement practice[]”) could
implicate “different constitutional principles.” Knotts, 460
U.S. at 283-84. The Supreme Court, in issuing Knotts, did
not want the case to stand for the proposition that new
technology that allows for more invasive surveillance would
automatically be permissible for the same reasons as allowed
in Knotts.

       In fact, in numerous cases, the Supreme Court and
Courts of Appeals have expressed caution about the extension
of their holdings regarding the permissibility of certain law
enforcement conduct to situations involving future
technology. See, e.g., Kyllo v. United States, 533 U.S. 27, 36
(2001) (“While the technology used in the present case was
relatively crude, the rule we adopt must take account of more
sophisticated systems that are already in use or in
development.”);8 see also United States v. Garcia, 474 F.3d
8
 See also Kyllo, 533 U.S. at 33-34 (“It would be foolish to
contend that the degree of privacy secured to citizens by the
Fourth Amendment has been entirely unaffected by the
advance of technology. For example, as the cases discussed
above make clear, the technology enabling human flight has
exposed to public view (and hence, we have said, to official

                              16
994 (7th Cir. 2007) (Posner, J.) (echoing the concern
expressed in Knotts that it might need to reevaluate its
conclusion if faced with a case concerning use of GPS
technology for mass surveillance); United States v. Robinson,
903 F. Supp. 2d 766, 785-87 (E.D. Mo. 2012) (“The need for
caution in this age of developing technology should be clear.
Other Supreme Court cases, by their rulings or their language,
have given notice that earlier pronouncements may not
control when the technology changes or the nature and degree
of intrusion changes.”).

        Even before Katz, when the Supreme Court articulated
the “reasonable expectation of privacy” test, the Supreme
Court was balancing the “need for effective law enforcement
against the right of privacy” in considering whether a
particular situation constituted an exception to the Fourth
Amendment’s warrant requirement. Johnson v. United
States, 333 U.S. 10, 14-15 (1948) (considering warrantless
searches based on probable cause). The law enforcement
community should have been on notice that they might not be
entitled to use warrantless twenty-four hour surveillance
through the use of new technology.

Consent

       Another critical difference between Knotts and Karo
and Katzin is the presence or absence of consent. The
majority derisively dismisses this issue as an “elaborate ruse.”

observation) uncovered portions of the house and its curtilage
that once were private. The question we confront today is
what limits there are upon this power of technology to shrink
the realm of guaranteed privacy.”) (citations omitted).

                              17
Majority Op. at 21. However, the “elaborate ruse” enabled
the law enforcement officers to place the beeper into a can of
ether, with the can owner’s consent. Karo, 468 U.S. at 708
(“With Muehlenweg’s consent, agents substituted their own
can containing a beeper for one of the cans in the shipment . .
. .”). Similarly, consent was present in Knotts because law
enforcement placed a beeper into a container of chloroform
with the consent of the chemical manufacturing company
where the suspect purchased the chloroform. Knotts, 460
U.S. at 278 (“With the consent of the Hawkins Chemical
Company, officers installed a beeper inside a five gallon
container of chloroform . . . .”).

        It is true that both of these cases established the
principle that no Fourth Amendment search occurs where
officers use beeper-based electronics to monitor an
automobile’s movement on public roads because a person has
no reasonable expectation of privacy regarding that
information. However, neither case addressed the direct
installation of a tracking device onto or into a vehicle, as is
the case here. First, the defendant in Knotts did not challenge
the original installation of the beeper, but only the use of the
information that it emitted. See id. at 286 (“I think this would
have been a much more difficult case if respondent had
challenged, not merely certain aspects of the monitoring of
the beeper installed in the . . . container . . . , but also its
original installation.”) (Brennan, J., concurring); Karo, 468
U.S. at 713 (“As the [Knotts] case came to us, the installation
of the beeper was not challenged; only the monitoring was at
issue.”).

      This distinction is important, particularly in light of
Jones’s determination that GPS tracking abridges Fourth
Amendment rights on the ground that the installation of the

                              18
GPS constituted a trespass. Jones, 132 S. Ct. at 949 (“The
Government physically occupied private property for the
purpose of obtaining information. We have no doubt that such
a physical intrusion would have been considered a ‘search’
within the meaning of the Fourth Amendment when it was
first adopted.”). When Knotts and Karo are applied to Katzin,
consent is a critical difference that renders their use as
binding appellate precedent doubtful.

Maynard Muddies the Waters

        Finally, there is the Maynard decision, which, if the
technological differences and consent distinctions were not
enough, sufficiently muddied the waters so that law
enforcement officers could not know whether the attachment
of a GPS device to the undercarriage of a vehicle would
violate the Fourth Amendment. In Maynard, the D.C. Circuit
split from three sister circuits to hold that prolonged GPS
surveillance constituted a search. Maynard, 615 F.3d at 563-
65. In so doing, the court rejected the Knotts-based argument
that a driver’s movements over the course of an entire month
are exposed to the public and therefore do not constitute
information shielded by the Fourth Amendment. Id. at 560.
This decision was rendered four months prior to the agents’
conduct at issue here.

       At the same time, the court in Maynard rejected the
applicability of the automobile exception to the warrant
requirement, holding that while the exception “permits the
police to search a car without a warrant if they have reason to
believe it contains contraband[, it] . . . does not authorize
them to install a tracking device on a car without the approval
of a neutral magistrate.” Id. at 567. A year later, the
Supreme Court granted certiorari, under the name United

                              19
States v. Jones. 131 S. Ct. 3064 (2011) (Jones and Maynard
were co-defendants). Maynard thus focused on the quality
and quantity of information gathered during the extended
surveillance.      Maynard, 615 F.3d at 562 (noting that
prolonged surveillance, unlike short-term surveillance,
exposes “what a person does repeatedly, what he does not do,
and what he does ensemble,” revealing more information than
an isolated trip).

       This case should have given law enforcement pause as
to the applicability of Knotts and Karo to the new world of
GPS. At the very least, they should have known that
prolonged surveillance could be an issue and one that could
be easily fixed by getting a search warrant from a neutral
magistrate.

       By its plain terms, the express holding in Davis is
inapposite to this case because I believe that Knotts and Karo
do not qualify as appropriate binding appellate precedent.
Neither case involved a physical trespass onto the target
vehicle; in both cases the police placed the beeper inside of a
container which was then loaded into the target vehicle by the
driver (all with the container owner’s permission). See Karo,
468 U.S. at 708; Knotts, 460 U.S. at 278. Additionally, both
Karo and Knotts addressed the use of beepers, which—as I
have already explained—are markedly different from GPS
trackers. See Maynard, 615 F.3d at 556-57.

III. Conclusion

       The majority’s good faith analysis is flawed because it
finds that, where the law is unsettled, law enforcement may
engage in constitutionally reckless conduct and still reap the
benefits of the good faith exception. Fourth Amendment

                              20
jurisprudence dictates a different outcome. When the law is
unsettled, law enforcement should not travel the road of
speculation, but rather they should demonstrate respect for the
constitutional mandate—obtain a warrant. Anything less
would require suppression. I cannot condone the majority’s
accommodation to law enforcement at the expense of our
civil liberties. I am compelled to dissent.

                              21
SMITH, J., Circuit Judge, dissenting, joined by McKEE,
Chief Judge, AMBRO, FUENTES, and GREENAWAY, JR.,
Circuit Judges.

        I join Judge Greenaway’s eloquent dissent in its
entirety. There is little that can be added to Judge
Greenaway’s devastating critique. I write here only to
expand on a worrisome facet of the majority’s reasoning.
Because Knotts1 and Karo2 are factually distinguishable and
did not hold that the specific conduct engaged in here by
government agents was permissible, i.e., attaching a GPS
device to Harry Katzin’s van, the majority is required to hold
that the officers’ conduct was consistent with the “rationale
underpinning” those decisions. References to Supreme Court
“rationale” are liberally sprinkled throughout the opinion.
See Majority op. at 18, 21, 22, 24, 31, 36, 38. If what the
majority is suggesting is that law enforcement officers may
rely not just on holdings, which are truly the stuff of
precedent, but also on appellate court rationale, I find such a
suggestion both troubling and impractical. What is the
limiting principle to be applied to these extrapolations? And
just what legal hermeneutic will lay police officers be
applying as they engage in such on-the-spot analysis of the
real-life cases they confront? I can discern no ready answer
to these questions.

1
    See United States v. Knotts, 460 U.S. 276 (1983).
2
    See United States v. Karo, 468 U.S. 705 (1984).
                                 1
        I do see, however, considerable tension between an
approach that permits law enforcement officers who invoke
the good faith exception to take refuge in the rationale of
certain Supreme Court cases, and the limiting language which
the Supreme Court itself chose to employ in Davis which
referred to binding precedent “specifically authoriz[ing]” a
particular police practice. United States v. Davis, 131 S. Ct.
2419, 2429 (2011).         The majority’s legal framework
eliminates the objectively reasonable source underpinning the
good faith exception: authorization from a neutral magistrate
or binding judicial precedent. Id. at 2428. The law
enforcement officers’ choice to commandeer the task of
Fourth Amendment legal analysis in the face of patent
ambiguity surely falls within the sort of “deliberate, reckless,
or grossly negligent” conduct that provides a strong
“deterrent value of exclusion” that may “outweigh the
resulting costs.” Id. at 2427 (quoting Herring v. United
States, 555 U.S. 135, 144 (2009)) (internal quotation marks
omitted). By not cabining to the judiciary the analysis of
ambiguous and, in this case, conflicting case law, the majority
turns the warrant requirement on its head.

      For this reason, and for those so ably expressed by
Judge Greenaway, I respectfully dissent.

                               2