Court Opinion

ID: 4683159
Source: CourtListenerOpinion
Date Created: 2021-05-03 07:01:29.326255+00
Date Added: 2024-06-11T08:04:13.443119
License: Public Domain

In the

    United States Court of Appeals
                For the Seventh Circuit
                    ____________________
Nos. 20-1236 & 20-2234
UNITED STATES OF AMERICA,
                                                   Plaintiﬀ-Appellee,
                                 v.

DAVID GIBSON and JERRY HARRIS,
                                             Defendants-Appellants.
                    ____________________

        Appeals from the United States District Court for the
         Northern District of Indiana, South Bend Division.
             No. 3:18-cr-33 — Jon E. DeGuilio, Judge.
                    ____________________

    ARGUED JANUARY 21, 2021 — DECIDED APRIL 30, 2021
                ____________________

   Before SYKES, Chief Judge, and MANION and ST. EVE, Circuit
Judges.
    ST. EVE, Circuit Judge. An informant gave South Bend po-
lice the number to a phone that drug dealers in the South
Bend area were supposedly using to sell drugs. To confirm
this tip, oﬃcers carried out a series of controlled buys in
which confidential informants or undercover oﬃcers called
the number and followed instructions to buy heroin. Relying
on the controlled buys, oﬃcers submitted an aﬃdavit to a
2                                        Nos. 20-1236 & 20-2234

state court judge requesting an order for the phone’s service
provider to share 30 days of precise, real-time GPS location
data for the phone. The state court judge issued a “court or-
der” granting the request. Relying on similar aﬃdavits, oﬃc-
ers later obtained two more court orders authorizing an addi-
tional 60 days of real-time tracking.
    The investigation ultimately led oﬃcers to two men at the
top of the drug-traﬃcking conspiracy: David Gibson and
Jerry Harris. Both defendants were federally indicted for con-
spiring to distribute heroin. Before trial, the district court de-
nied their motion to suppress evidence obtained through the
cellphone tracking. The court treated the state court orders as
valid search warrants for the tracking. At trial, oﬃcers and co-
operators testified to the large-scale drug-traﬃcking scheme
that the defendants had overseen. The jury ultimately con-
victed both defendants of conspiring to distribute one kilo-
gram or more of heroin. At sentencing, the district court found
that the defendants had conspired to distribute a total of 10.5
kilograms of heroin. The defendants now appeal the court’s
denial of their motion to suppress. Harris also challenges the
drug-quantity calculations at trial and sentencing, the court’s
limits on his cross-examination of the cooperators at trial, and
his sentence. We aﬃrm the district court’s well-reasoned rul-
ings across the board.
                         I. Background
A. The Investigation
    In late 2016 Ryan Williams was charged in Indiana state
court for selling drugs. In March 2017, as an act of coopera-
tion, Williams provided South Bend police the number to a
phone (ending in -5822) that, he claimed, drug dealers in the
Nos. 20-1236 & 20-2234                                           3

South Bend area used to sell drugs. Over the next several
months, oﬃcers made 28 controlled buys using the phone
number. In these controlled buys, a confidential informant or
undercover oﬃcer would call the number and follow instruc-
tions to buy heroin. Each controlled buy involved half-gram
increments of heroin. Diﬀerent dealers, including Williams
himself on occasion, would show up to deliver the drugs. The
dealers would sell indiscriminately to anyone who called the
number. At meeting spots, cars lined up to buy drugs.
    A few months into the investigation, oﬃcers sought to es-
tablish surveillance of the phone’s location. In July 2017, oﬃc-
ers submitted an aﬃdavit to an Indiana state court judge re-
questing an order for Sprint, the phone’s service provider, to
supply 30 days of precise, real-time GPS location data for the
phone. The aﬃdavit described two separate controlled buys
in which a confidential informant had called the phone and
met someone who sold him heroin. One of the controlled buys
had occurred two and a half months earlier; the other had oc-
curred the day before. The aﬃdavit did not cite Federal Rule
of Criminal Procedure 41 (which governs search warrants
based on probable cause). Indeed, the aﬃdavit did not men-
tion probable cause at all. Instead, it cited federal statutes gov-
erning the installation of mobile tracking devices, pen regis-
ters, and trap and trace devices. See 18 U.S.C. §§ 3117, 3124.
    Based on the aﬃdavit, an Indiana judge signed a “court
order” finding probable cause to believe that the user of the
-5822 phone had engaged in illegal drug possession and traf-
ficking, and that precise tracking of the phone’s location
would facilitate the user’s apprehension. Thus, the judge or-
dered Sprint to supply 30 days of precise, real-time GPS loca-
tion data for the phone. As authority for the order, the judge
4                                       Nos. 20-1236 & 20-2234

cited Rule 41, the Stored Communications Act, see 18 U.S.C.
§ 2703, and the federal statutes governing mobile tracking de-
vices, pen registers, and trap and trace devices, see 18 U.S.C.
§§ 3117, 3123, 3124. Per the order, Sprint gave oﬃcers 24-hour
access to the phone’s precise location for 30 days.
    At the end of the 30-day period, oﬃcers submitted a sec-
ond aﬃdavit, requesting 30 more days of real-time cellphone
tracking. The aﬃdavit explained that, since obtaining the first
court order, oﬃcers had carried out several more controlled
buys using the same phone number. It described one of them
in detail. The aﬃdavit added that “this is a very complex or-
ganization with approximately fifteen members who utilize
the [phone] to facilitate drug traﬃcking.” In all other respects,
the second aﬃdavit mirrored the first. Based on the aﬃdavit,
the state court judge signed another order, essentially identi-
cal to the first, authorizing 30 more days of real-time cell-
phone tracking.
    The same series of events happened one more time. At the
end of the second 30-day period, oﬃcers submitted a third af-
fidavit, requesting 30 more days of GPS tracking data for the
phone. This aﬃdavit closely resembled the second one. It de-
scribed in detail “one of several undercover oﬃcer buys”
made in the previous 30-day period. The state court judge
signed another materially identical order authorizing 30 more
days of real-time cellphone tracking.
    Oﬃcers eventually recovered the -5822 phone in October
2017 when they pulled over a man named Raymond Love for
a traﬃc violation. Love had two “flip phones” on him, includ-
ing the -5822 phone. Throughout the traﬃc stop, both phones
rang nonstop.
Nos. 20-1236 & 20-2234                                       5

   While tracking the -5822 phone, oﬃcers observed that it
was located at various times in houses that they later con-
nected to Gibson and Harris. Oﬃcers executed a search war-
rant on the home associated with Harris, where they found a
digital scale and almost $4,000 cash.
B. Charges and Motion to Suppress
    A federal grand jury indicted Gibson and Harris with one
count of conspiring to distribute more than one kilogram of
heroin between March and October 2017. See 21 U.S.C.
§§ 841(b)(1)(A), 846. Before trial, the defendants moved to
suppress all evidence obtained through the phone tracking.
They maintained that oﬃcers could not track the phone with-
out a search warrant. Following a hearing, the district court
denied the defendants’ motion to suppress. It ruled that the
state court orders were valid warrants for the phone tracking.
C. Trial
    The cases against Gibson and Harris were consolidated for
trial. Various law enforcement oﬃcers testified, as did a few
cooperating witnesses who had participated in the drug-traf-
ficking conspiracy. Two of these cooperators were Williams
and Loveless Daniel Naylor. Like Williams, Naylor was one
of the street-level dealers who sold drugs directly to calling
customers. Before the defendants went to trial, Williams pled
guilty to conspiring to distribute one kilogram or more of her-
oin. Naylor pled guilty to possession with intent to distribute
heroin.
   Williams testified to the details of the drug-traﬃcking op-
eration. Gibson ran the operation and Harris was his “right-
hand man.” There were 20 to 25 dealers who worked in shifts.
Gibson or Harris gave the dealers phones and “packs” of
6                                      Nos. 20-1236 & 20-2234

drugs to sell. The packs contained 22 to 24 individually pack-
aged half-gram bags of heroin. A single dealer could go
through as many as five or six packs on a weekend day. Most
customers bought between one and ten half-gram bags at a
time, but some bought up to fifteen. There were two phone
numbers that customers could call: the -5822 number and an-
other number ending in -9243. Williams testified that a trans-
action required, at most, “probably about three” phone calls.
An oﬃcer involved in the controlled buys testified that a suc-
cessful buy generally required between one and four calls,
though sometimes more were necessary. Naylor testified sim-
ilarly regarding the details of the drug-traﬃcking operation.
He added that, between March and October 2017, Gibson
gave him between 600 and 700 grams of heroin to sell.
   Over Harris’s objection, the court forbade defense counsel
from cross-examining the cooperating witnesses about the
specific sentences they hoped to avoid by testifying for the
government. The court explained that defense counsel could
ask about mandatory minimums and “substantial sentences”
but could not reference specific terms of imprisonment. Oth-
erwise the jury might infer what sentences the defendants
themselves would receive if convicted.
    The government introduced only 6.5 grams of heroin at
trial. To prove the full quantity of drugs involved in the con-
spiracy, the government called DEA Task Force Oﬃcer Joseph
Focosi. Oﬃcer Focosi used two diﬀerent formulas to calculate
drug quantity. First, he relied on Williams’s testimony that he
alone could sell up to six “packs” per day, with each pack con-
taining 22 to 24 half-gram bags. Assuming that the dealers
sold only one pack per day, and rounding the amount of her-
oin in a pack down to 10 grams, Oﬃcer Focosi testified that
Nos. 20-1236 & 20-2234                                           7

the dealers would have sold 2.1 kilograms of heroin over a
seven-month period (10 grams x 210 days = 2,100 grams). De-
fense counsel did not object to this testimony.
    Oﬃcer Focosi’s second formula extrapolated drug quan-
tity from phone calls. A DEA analyst had testified that, from
the end of March 2017 through mid-October 2017, there were
about 50,000 successful calls to the -5822 phone and 34,000
successful calls to the -9243 phone. Conservatively estimating
that each transaction involved six phone calls and half a gram
of heroin, Oﬃcer Focosi testified that the conspiracy involved
7 kilograms of heroin (84,000 total calls / 6 calls per transaction
= 14,000 transactions x .5 grams per transaction = 7,000 grams).
   Harris’s counsel objected that the underlying testimony
about calls per transaction had “not been that precise” and
that Oﬃcer Focosi was oﬀering an opinion based on his “ex-
perience and expertise” in deciding what number of calls to
use. The district court overruled the objection. The court ex-
plained that whether six calls was a precise estimate went to
the weight of the testimony, and that Oﬃcer Focosi was rely-
ing on what he had learned from the investigation rather than
“exercising any experience.”
    Defense counsel also objected to Oﬃcer Focosi’s assump-
tion that all 84,000 calls were between dealers and customers,
when “presumably, there would be calls between a dealer and
other people as well.” The court overruled this objection, too,
explaining: “I think that’s true, but that, again, goes to weight,
and I think that’s something you can explore on cross exami-
nation.”
   On cross-examination, Oﬃcer Focosi testified that he
chose six calls per transaction because “it was more than one
8                                        Nos. 20-1236 & 20-2234

through four” (the range that witnesses had testified to). He
admitted that he could have chosen a larger number, any-
where from 5 to 24. He also admitted that he did not know the
content of specific calls and conceded that some calls “might
have had nothing to do with heroin deals.”
    The jury found both defendants guilty of conspiring to
distribute one kilogram or more of heroin.
D. Sentencings
    The probation oﬃcer calculated each defendant’s advi-
sory Guideline range as 360 months to life. Both defendants
had a criminal history category of VI, but Gibson’s oﬀense
level (38) was one point higher than Harris’s (37) because Gib-
son was an “organizer or leader” of the drug-traﬃcking oper-
ation whereas Harris was a “manager or supervisor.” See
USSG § 3B1.1.
    Harris objected to the probation oﬃcer’s conclusion that
he had conspired to distribute 10.5 kilograms of heroin. See
USSG § 2D1.1(b)(18)(3) (increasing oﬀense level for crimes in-
volving 10 to 30 kilograms of heroin). To reach that number,
the probation oﬃcer used Oﬃcer Focosi’s second formula
from trial. Unlike Oﬃcer Focosi, however, the probation of-
ficer assumed, based on the “most conservative” estimate at
trial, that every drug sale required four, rather than six, calls
(84,000 total calls / 4 calls per transaction = 21,000 transactions
x .5 grams per transaction = 10,500 grams). Harris objected to
this methodology as “speculative and not reasonable.” The
court overruled his objection. It found, based on the evidence
at trial, that the proposed drug-quantity calculation was
“both certain and reasonable.” There was no evidence that
any dealers had used the shared drug phones to make
Nos. 20-1236 & 20-2234                                       9

personal calls, and even if they had, the number of personal
calls “would have to be dramatic to defeat the finding of ten
or more kilograms” given how conservative the four-call and
half-gram numbers were.
    The court sentenced both defendants well below the low
end of the Guidelines range. Specifically, it sentenced Gibson
to 240 months’ imprisonment and Harris to 262 months. The
court explained the discrepancy at Harris’s sentencing. At 47,
Gibson was a bit older than Harris, who was 38. Moreover,
Gibson had recently received a 144-month consecutive sen-
tence in another case for carrying a firearm in relation to a
drug-traﬃcking crime. See 18 U.S.C. § 924(c). In the court’s
view, Gibson’s older age and consecutive sentence influenced
his risk of reoﬀending upon release. The same calculus did
not apply to Harris, who was younger and not facing a con-
secutive sentence. The court went on to determine that Harris
warranted a three-level reduction, which corresponded to a
sentencing range of 262 to 327 months. It found that “a sen-
tence in this range will satisfy the purposes of the sentencing
statute” and further “note[d] that even if I calculated the
Guideline range diﬀerently in the first instance, I would vary
to this same range based on my consideration of the 3553(a)
factors as a whole.” A review of the § 3553(a) factors “per-
suade[d] the Court that a sentence at the low end of the now
revised recommended sentencing range is appropriate.” The
defendants timely appealed.
                         II. Discussion
   On appeal the defendants challenge the district court’s ad-
mission of evidence obtained through the cellphone tracking.
Harris also challenges the drug-quantity calculations at trial
and sentencing, the district court’s limits on his cross-
10                                       Nos. 20-1236 & 20-2234

examination of cooperating witnesses, and the reasonable-
ness of his sentence.
A. Cellphone Tracking
    The defendants’ first contention is that oﬃcers violated the
defendants’ Fourth Amendment rights by tracking the loca-
tion of the -5822 phone without a warrant based on probable
cause. They submit that the “court orders” authorizing the
tracking were not valid warrants because they cited the Stored
Communications Act, which requires a lesser showing than
probable cause. See 18 U.S.C. § 2703(d) (requiring only “spe-
cific and articulable facts showing that there are reasonable
grounds to believe that the [information sought is] relevant
and material to an ongoing criminal investigation”); see also
United States v. Castro-Aguirre, 983 F.3d 927, 934 (7th Cir. 2020)
(describing this standard as “significantly lower than the
probable-cause requirement for a warrant”). They contend as
well that the underlying aﬃdavits did not supply probable
cause for a search warrant.
     A Fourth Amendment “search” generally requires a war-
rant based on probable cause. Carpenter v. United States, 138 S.
Ct. 2206, 2221 (2018); Katz v. United States, 389 U.S. 347, 357
(1967). The government does not dispute that the cellphone
tracking in this case amounted to a “search” requiring a war-
rant, and we assume for purposes of this appeal that it did.
Nonetheless, the government maintains that the search was
lawful because a valid warrant authorized it. The district
court agreed and denied the defendants’ motion to suppress.
We review the district court’s legal conclusions de novo and
its factual findings for clear error. United States v. Jackson, 962
F.3d 353, 357 (7th Cir. 2020).
Nos. 20-1236 & 20-2234                                       11

     A valid search warrant “require[s] only three things”: (1)
an independent magistrate issuing it; (2) a showing of proba-
ble cause “that the evidence sought will aid in a particular ap-
prehension or conviction for a particular oﬀense”; and (3) a
particular description of “the things to be seized, as well as
the place to be searched.” Dalia v. United States, 441 U.S. 238,
255 (1979) (internal quotations and citations omitted); accord
United States v. Brewer, 915 F.3d 408, 414 (7th Cir. 2019). Sub-
stance matters more than form in this context. Thus, a court
order can satisfy the warrant requirement even if it is not la-
beled a “warrant.” Dalia, 441 U.S. at 256 (wiretap order was a
valid warrant); United States v. Ning Wen, 477 F.3d 896, 898
(7th Cir. 2007) (same). And a warrant that finds probable
cause and cites Rule 41 satisfies the Fourth Amendment even
if it also recites the lower standard of the Stored Communica-
tions Act. United States v. Sanchez-Jara, 889 F.3d 418, 421 (7th
Cir. 2018).
    The court orders in this case satisfy the requirements for a
search warrant. First, the defendants do not contend, and
there is no reason to believe, that the state court judge who
issued the orders was anything but neutral and detached.
Next, the orders cited Rule 41 and found probable cause to
believe that the cellphone tracking would lead to the appre-
hension of drug traﬃckers. Last, the orders particularly de-
scribed the object of the search: the location of the -5822
phone. With respect to the particularity requirement, we have
held that “a warrant authorizing police to follow an identified
phone, to see where it goes and what numbers it calls, partic-
ularly describes the evidence to be acquired.” Sanchez-Jara,
889 F.3d at 421; accord Brewer, 915 F.3d at 414 (“Judges must
describe the specific person, phone, or vehicle to be tracked to
satisfy the Fourth Amendment’s particularity requirement.”)
12                                       Nos. 20-1236 & 20-2234

(emphasis added). It makes no diﬀerence that the court orders
were not labeled “warrants,” or that they cited, in addition to
Rule 41, other statutes including the Stored Communications
Act. See Dalia, 441 U.S. at 256; Ning Wen, 477 F.3d at 898;
Sanchez-Jara, 889 F.3d at 421.
    We reject the defendants’ contention that the underlying
aﬃdavits did not supply probable cause. Probable cause for
issuance of a search warrant exists if there is “a fair probabil-
ity that contraband or evidence of a crime will be found in a
particular place.” Illinois v. Gates, 462 U.S. 213, 238 (1983). The
state court judge’s finding of probable cause “carries a strong
presumption of correctness.” Sanchez-Jara, 889 F.3d at 421.
Our task as “a reviewing court is simply to ensure that the
[state court judge] had a substantial basis for concluding that
probable cause existed.” Gates, 462 U.S. at 238–39 (internal
quotations, citation, and alterations omitted).
    We have held that a properly executed controlled buy is
generally “a reliable indicator as to the presence of illegal
drug activity.” United States v. Sidwell, 440 F.3d 865, 869 (7th
Cir. 2006); see also United States v. Bacon, 991 F.3d 835, 839 (7th
Cir. 2021) (“[C]ontrolled buys ordinarily go a long way to-
ward establishing probable cause.”). Here, the aﬃdavits de-
scribed several controlled buys in detail, including the ar-
rangement of the buys through calls to the -5822 phone. The
first aﬃdavit described two controlled buys involving the
same confidential informant, whom oﬃcers searched, wired,
and closely monitored. On two separate occasions, the confi-
dential informant called the -5822 phone and successfully
bought heroin, which he then turned over to the police. The
second and third aﬃdavits referenced the earlier orders and
described additional, more recent controlled buys in which
Nos. 20-1236 & 20-2234                                          13

undercover oﬃcers called the same phone and bought heroin.
We have little trouble concluding that these controlled buys
gave the state court judge a substantial basis for a finding of
probable cause to track the location of the phone suﬃcient to
support each of its orders. See Gates, 462 U.S. at 238–39.
    The defendants do not contest the method or execution of
the controlled buys. Instead, they complain that one of the
controlled buys in the first aﬃdavit was two and a half
months old. That is true, but the other controlled buy in the
first aﬃdavit took place the day before the state court judge
signed the first order. So, to the extent that the first controlled
buy might have been “stale,” the “more recent” controlled
buy mitigated that issue by showing that “the same kind of
criminal activity continued” through the present day. United
States v. Rees, 957 F.3d 761, 769–70 (7th Cir. 2020).
    The defendants also suggest that the aﬃdavits did not
supply probable cause to track them, given that the aﬃdavits
did not mention them by name. But probable cause for a
search warrant need not be tied to any particular person. See
Gates, 462 U.S. at 238 (requiring “a fair probability that con-
traband or evidence of a crime will be found in a particular
place”) (emphasis added); see also Bacon, 991 F.3d at 841. In this
case, oﬃcers knew that the users of the -5822 phone were sell-
ing drugs, but they did not know who the users were. That is
why they wanted to track the phone—to apprehend the users
for drug traﬃcking. In line with that mission, the state court
judge found probable cause to believe that the cellphone
tracking would facilitate the apprehension of drug traﬃckers.
This finding was enough for probable cause, even though the
judge did not identify Gibson or Harris by name. See Dalia,
441 U.S. at 255 (“[T]hose seeking the warrant must
14                                      Nos. 20-1236 & 20-2234

demonstrate to the magistrate their probable cause to believe
that ‘the evidence sought will aid in a particular apprehension
or conviction’ for a particular oﬀense.” (quoting Warden, Md.
Penitentiary v. Hayden, 387 U.S. 294, 307 (1967))).
    We therefore conclude that oﬃcers had a valid warrant to
track the -5822 phone. The district court correctly denied the
defendants’ motion to suppress. We need not address the gov-
ernment’s alternative arguments that the good-faith excep-
tion applies, see United States v. Leon, 468 U.S. 897, 922 (1984),
and that the defendants lack “standing” to challenge the cell-
phone tracking, see Byrd v. United States, 138 S. Ct. 1518, 1530
(2018). We note, however, that an oﬃcer’s reliance on a war-
rant presumptively establishes that the oﬃcer acted in good
faith in carrying out a search. Leon, 468 U.S. at 922; United
States v. Lickers, 928 F.3d 609, 618 (7th Cir. 2019). Moreover,
we are skeptical that either defendant has standing to chal-
lenge the cellphone tracking. There was no evidence at the
suppression hearing that either defendant personally pos-
sessed or used the -5822 phone during the 90-day tracking pe-
riod. The defendants maintain that the government conceded
the defendants’ possession of the phone. But even if that is
true, the evidence from trial suggests that the defendants had,
at most, on-and-oﬀ possession of this cellphone that approxi-
mately two dozen drug dealers shared to sell drugs. And
there is no evidence that either defendant ever used the phone
for personal, rather than commercial, purposes. Just as drug
dealers who briefly occupy stash houses while packaging
drugs lack a legitimate expectation of privacy in the stash
houses, the defendants here would seem to lack a legitimate
expectation of privacy in the whereabouts of a shared drug
phone. See Minnesota v. Carter, 525 U.S. 83, 90–91 (1998); United
States v. Gray, 491 F.3d 138, 147 (4th Cir. 2007); H. Hunter
Nos. 20-1236 & 20-2234                                         15

Bruton, Note, The Shifting Nature of Stash-House Standing and
Sentencing, 42 N.Y.U. Rev. L. & Soc. Change 351, 358 (2018).
Ultimately, we need not resolve this issue. And given the par-
ties’ dispute as to whether the government conceded the de-
fendants’ possession of the phone, it is best to leave it for an-
other day.
B. Drug-Quantity Calculations
   Apart from the cellphone tracking, Harris takes issue with
the drug-quantity calculations at trial and at his sentencing.
   1. Trial
    Harris submits that Oﬃcer Focosi’s trial testimony was
unreliable and ran afoul of the rules governing expert testi-
mony. See Fed. R. Evid. 702; Fed. R. Crim. P. 16(a)(1)(G); see
also United States v. Gaytan, 649 F.3d 573, 582 (7th Cir. 2011).
As such, he challenges the suﬃciency of the drug-quantity ev-
idence and seeks to overturn the jury’s finding that he con-
spired to distribute at least one kilogram of heroin. See 21
U.S.C. § 841(b)(1)(A) (providing a mandatory-minimum sen-
tence for oﬀenses involving one kilogram or more of heroin).
    Harris did not move for a judgment of acquittal, so we re-
view the jury’s drug-quantity determination only for a “man-
ifest miscarriage of justice.” United States v. Chaparro, 956 F.3d
462, 468 (7th Cir. 2020) (internal quotations and citation omit-
ted). This means that the jury’s verdict stands unless “the rec-
ord is devoid of evidence pointing to guilt, or … the evidence
on a key element of the oﬀense was so tenuous that a convic-
tion would be shocking.” Id. (internal quotations and citation
omitted).
    Harris’s challenge to the jury’s drug-quantity determina-
tion goes nowhere because the government oﬀered the jury
16                                        Nos. 20-1236 & 20-2234

two independent ways to find that Harris conspired to dis-
tribute more than one kilogram of heroin and Harris chal-
lenges only one of these methods. First, Oﬃcer Focosi testi-
fied, based on Williams’s testimony that he could sell up to
six “packs” of heroin on a weekend day, the conspiracy in-
volved 2.1 kilograms of heroin. To reach that number, Oﬃcer
Focosi conservatively estimated that the dealers sold only one
10-gram pack per day during the seven-month conspiracy (10
grams x 210 days = 2,100 grams). Oﬃcer Focosi’s second for-
mula extrapolated drug quantity from phone calls. A DEA an-
alyst had testified that there were about 84,000 successful calls
to the two drug phones during the conspiracy. Conservatively
estimating that each transaction involved six phone calls and
half a gram of heroin, Oﬃcer Focosi testified that the conspir-
acy involved 7 kilograms of heroin (84,000 total calls / 6 calls
per transaction = 14,000 transactions x .5 grams per transac-
tion = 7,000 grams). Harris claims that Oﬃcer Focosi’s second
formula was inadmissible expert testimony that the govern-
ment failed to timely disclose. But even if that is true, Harris
has never challenged Oﬃcer Focosi’s first formula. Oﬃcer
Focosi’s first formula independently sustains the jury’s drug-
quantity finding and renders harmless any error in the district
court’s admission of Oﬃcer Focosi’s second formula. See Fed.
R. Crim. P. 52(a); United States v. Jett, 908 F.3d 252, 265 (7th Cir.
2018). Thus, Harris has not identified a prejudicial error in the
drug-quantity calculation at trial—much less a manifest mis-
carriage of justice. Chaparro, 956 F.3d at 468.
     2. Sentencing
   Harris also challenges the district court’s calculation of the
drug quantity at sentencing. Whereas the government asked
the jury to find that Harris conspired to distribute one
Nos. 20-1236 & 20-2234                                          17

kilogram or more of heroin, at sentencing the district court
had to calculate the actual amount of heroin involved in the
conspiracy and reasonably foreseeable to Harris. See USSG
§ 2D1.1, comment. (n.5); USSG § 1B1.3(a)(1)(B). Relying on the
probation oﬃcer’s recommendations and the evidence at trial,
the court found that the government had established by a pre-
ponderance of the evidence that Harris conspired to distrib-
ute 10.5 kilograms of heroin. The court reached this number
by applying Oﬃcer Focosi’s second formula and assuming
that each drug transaction required four, rather than six, calls
(84,000 total calls / 4 calls per transaction = 21,000 transactions
x .5 grams per transaction = 10,500 grams). Harris maintains
that this calculation rested on speculative and unreliable data.
More specifically, he claims that 4 calls per transaction is an
arbitrary estimate, and that there is no evidence that all 84,000
calls were drug related.
   A defendant attacking a district court’s factual findings at
sentencing has “a steep hill to climb.” United States v. Ranjel,
872 F.3d 815, 818 (7th Cir. 2017). We “will not disturb a sen-
tencing court’s factual findings unless they are clearly errone-
ous.” Id. The government must prove drug quantity by a pre-
ponderance of the evidence. United States v. Medina, 728 F.3d
701, 705 (7th Cir. 2013).
    The Sentencing Guidelines tie a defendant’s oﬀense level
to the quantity of drugs involved in the oﬀense. See USSG
§ 2D1.1(c). In a drug conspiracy, “each conspirator is respon-
sible for both the drug quantities directly attributable to him
and amounts involved in reasonably foreseeable dealings by
co-conspirators.” United States v. Austin, 806 F.3d 425, 431 (7th
Cir. 2015); see USSG § 1B1.3(a)(1)(B). If the quantity of drugs
seized “does not reflect the scale of the oﬀense,” a court must
18                                       Nos. 20-1236 & 20-2234

“approximate” the total drug quantity. USSG § 2D1.1, com-
ment. (n.5). To make such an approximation, the court “may
consider, for example, the price generally obtained for the
controlled substance, financial or other records, similar trans-
actions in controlled substances by the defendant, and the size
or capability of any laboratory involved.” Id.
    Drug-quantity calculations are “not an exact science.”
United States v. Sewell, 780 F.3d 839, 849 (7th Cir. 2015). “De-
termining drug quantities under the Sentencing Guidelines is
often diﬃcult, and district courts may make reasonable
though imprecise estimates based on information that has in-
dicia of reliability.” United States v. Bozovich, 782 F.3d 814, 818
(7th Cir. 2015). The Guidelines do not permit “‘nebulous eye-
balling,’” but “some amount of reasoned ‘speculation and rea-
sonable estimation’” is permissible. United States v. Hollins,
498 F.3d 622, 631 (7th Cir. 2007) (quoting United States v. Jar-
rett, 133 F.3d 519, 530 (7th Cir. 1998)).
    Here, the district court properly relied on the evidence in
the record to conservatively calculate the drug quantity. Its
calculation was not clear error. All three numbers that the
court plugged into Oﬃcer Focosi’s second formula (84,000 to-
tal calls / 4 calls per transaction = 21,000 transactions x .5
grams per transaction = 10,500 grams) had a firm basis in the
record. Harris does not challenge the half-gram-per-transac-
tion figure, nor could he. Williams, Naylor, and an oﬃcer in-
volved in the controlled buys testified that the heroin was pre-
packaged and sold in half-gram increments. Most customers
bought between one and ten half-gram bags at a time, though
some bought as many as fifteen. One half-gram bag per trans-
action was thus an extremely conservative estimate.
Nos. 20-1236 & 20-2234                                         19

    Harris describes the four-calls-per-transaction estimate as
arbitrary. But Williams, who regularly sold heroin to buyers
who called the drug phones, testified that the transactions re-
quired, at most, three calls. Further, an oﬃcer who partici-
pated in the controlled buys testified that the transactions
usually required between one and four calls. Given this evi-
dence, the four-call estimate was reliable and indeed very
conservative. Harris counters that the discrepancy between
the calls-per-transaction figure at trial (six calls) and sentenc-
ing (four calls) demonstrates the arbitrariness of both num-
bers. But at trial, the government sought to prove a minimum
drug quantity beyond a reasonable doubt. See 21 U.S.C.
§ 841(b)(1)(A) (providing a mandatory-minimum sentence for
oﬀenses involving one kilogram or more of heroin); see also
Alleyne v. United States, 570 U.S. 99, 103 (2013) (holding any
fact that increases the penalty for a crime must be proven to a
jury beyond a reasonable doubt). The actual quantity of drugs
was not an element of the oﬀense. See United States v. Abdulahi,
523 F.3d 757, 760 (7th Cir. 2008). At sentencing, by contrast,
the government sought to prove the actual drug quantity by
a preponderance of the evidence. See id. at 760–61. Given the
diﬀerent burdens of proof and required showings, there was
nothing inconsistent about using diﬀerent estimates of calls
per transaction at trial and sentencing.
    Harris directs most of his criticism to the third figure—
84,000 total calls. But this number, too, had a firm basis in the
record. A DEA analyst reviewed phone records and testified
that there were 84,000 successful calls to the two drug phones
during the conspiracy. Harris insists that any number of these
calls could have been unrelated to drugs. And to be sure, Of-
ficer Focosi conceded at trial that he could not rule out the
possibility that some of the calls were unrelated to drug
20                                     Nos. 20-1236 & 20-2234

transactions. But, as the district court recognized, there is no
evidentiary support for Harris’s speculative hypothesis that
the two dozen drug dealers who shared the drug phones were
also receiving personal calls on the phones. All evidence
points to the opposite conclusion—these were drug phones
that on-duty dealers used to continuously make drug sales.
When Williams was asked at trial who called the phones, he
responded, “people who wanted to buy drugs.” Naylor testi-
fied that “customers” called the phones. The government had
to prove drug quantity by a preponderance of the evidence—
not to an absolute certainty. On these facts, the district court
did not err in calculating the heroin quantity.
    Harris relies heavily on United States v. Howard, 80 F.3d
1194 (7th Cir. 1996). But the problem in Howard was the pro-
bation oﬃcer’s failure to explain the evidentiary basis for the
drug-quantity calculation. As we said: “Where either the pro-
bation oﬃcer or the prosecution oﬀers an estimate of the drug
quantities for which the defendant should be held responsi-
ble, the defendant ought to be on notice of all assumptions,
rationale, and methodology underlying the calculation.” Id. at
1204. Here, the government’s methodology was transparent.
It derived from specific testimony that the government of-
fered at trial. Harris tested the reliability of that testimony
through cross-examination. Indeed, he bases his challenge to
the court’s drug-quantity calculation primarily on conces-
sions that he obtained from Oﬃcer Focosi at trial. Unlike the
defendant in Howard, Harris could, and did, challenge the
government’s methodology because he knew the evidentiary
basis for it. A disputed evidentiary basis is not the same thing
as no evidentiary basis. This distinction renders Harris’s out-
of-circuit citations equally inapposite. See United States v.
Sepulveda, 15 F.3d 1161, 1198 (1st Cir. 1993); United States v.
Nos. 20-1236 & 20-2234                                         21

Shonubi, 998 F.2d 84, 90 (2d Cir. 1993); United States v. Collado,
975 F.2d 985, 998 (3d Cir. 1992).
    Harris also complains that the government’s use of phone
calls to extrapolate drug quantity was unprecedented. That is
not entirely true, as other circuits have upheld drug-quantity
calculations extrapolated, at least in part, from phone calls.
See, e.g., United States v. Green, 40 F.3d 1167, 1175 (11th Cir.
1994). More importantly, though, the district court’s job was
to make a reasonable estimate of drug quantity on the record
before it. Austin, 806 F.3d at 431. This was a unique case. The
evidence showed that Gibson and Harris oversaw a large
drug-traﬃcking operation in which approximately two dozen
drug dealers sold drugs indiscriminately to anyone who
called either of two shared drug phones. The court had to ap-
proximate the quantity of drugs involved in this conspiracy,
and it did so reasonably. Nothing required the court to locate
a prior case approving of its methodology for calculating
drug quantity.
    For these reasons, the district court did not clearly err in
calculating the drug quantity at Harris’s sentencing. And
even if it did, any error was harmless. At Harris’s sentencing,
the court said on the record that, even if it had calculated the
Guidelines range diﬀerently, it would vary to the same range
and impose the same sentence based on its independent con-
sideration of the sentencing factors under 18 U.S.C. § 3553(a).
When a sentencing court bases its sentence on the § 3553(a)
factors and says it would have imposed the same sentence re-
gardless of the Guidelines range, an error in calculating the
Guidelines range may be harmless. See, e.g., United States v.
Snyder, 865 F.3d 490, 500–01 (7th Cir. 2017); Molina-Martinez v.
United States, 136 S. Ct. 1338, 1346–47 (2016). That happened
22                                      Nos. 20-1236 & 20-2234

here. The district judge presided over the trial and knew the
facts of the conspiracy inside and out. He thoroughly ex-
plained his sentence and anchored it in the § 3553(a) factors.
Even if his drug-quantity calculation was wrong, the district
judge knew the scale of the conspiracy and Harris’s role in it.
He explained that he would have imposed the same sentence
regardless of the Guidelines range. On these facts, any error
in calculating drug quantity was harmless.
C. Cross-Examination of Cooperators
    Harris argues next that the district court improperly con-
strained his cross-examination of cooperating witnesses. He
says he should have been allowed to question Williams and
Naylor about the specific sentences they hoped to avoid by
testifying for the government.
    The Sixth Amendment guarantees a criminal defendant
the opportunity to eﬀectively cross-examine witnesses
against him. United States v. Trent, 863 F.3d 699, 704 (7th Cir.
2017). But this right is not absolute: “a district court has dis-
cretion to place reasonable limits on cross-examination, espe-
cially when necessary to prevent irrelevant or confusing evi-
dence from being presented to the jury.” Id. Such irrelevant or
confusing evidence includes “information from which [the
jury] could infer defendants’ potential sentences.” Id. at 705.
    Federal juries do not decide sentences in noncapital cases,
so specific sentencing information “might confuse or mislead
the juries in their true task: deciding defendants’ guilt or in-
nocence.” Id. The risk is that “the reality of a serious sentence
could prejudice the jury and cause it to acquit the defendants
of crimes they actually committed.” United States v. Hunter,
932 F.3d 610, 619 (7th Cir. 2019). For these reasons, we have
Nos. 20-1236 & 20-2234                                         23

held that district courts may in some circumstances bar de-
fense counsel from cross-examining cooperating witnesses
about “the exact length” of the witness’s potential sentence.
Trent, 863 F.3d at 706; Hunter, 932 F.3d at 620.
    Our standard for reviewing a district court’s limit on
cross-examination “depends on whether the court’s limit ‘di-
rectly implicates the core values of the Confrontation
Clause.’” Trent, 863 F.3d at 704 (quoting United States v. Re-
cendiz, 557 F.3d 511, 530 (7th Cir. 2009)). If it does, our review
is de novo; if it does not, we review for abuse of discretion. Id.
The core values of the Confrontation Clause include allowing
the defendant “to expose a witness’s motivation for testifying,
his bias, or his possible incentives to lie.” Id. at 705 (quoting
Recendiz, 557 F.3d at 530). “But that value is only oﬀended
when ‘the defense is completely forbidden from exposing the
witness’s bias.’” Id. (quoting United States v. Sanders, 708 F.3d
976, 990 (7th Cir. 2013)). When the defense has “a reasonable
opportunity to question witnesses about their biases, the Sixth
Amendment is not implicated.” Id.
    The district court’s limits on Harris’s cross-examination of
Williams and Naylor did not implicate the core values of the
Sixth Amendment. The court imposed a limited restriction on
Harris’s cross-examination. It only forbade Harris from ques-
tioning Williams and Naylor about the exact sentences they
hoped to avoid. It otherwise gave Harris free reign to ask the
witnesses about mandatory minimums and “substantial sen-
tences.” See Trent, 863 F.3d at 705–06.
   And Harris took full advantage. Williams testified on
cross-examination that, although he was a felon with two
guns on him at the time of his arrest, the government never
charged him with being a felon in possession of a firearm. See
24                                      Nos. 20-1236 & 20-2234

18 U.S.C. § 922(g)(1). The government also never charged him
with carrying a firearm in relation to a drug-traﬃcking
crime—an oﬀense that, he admitted, carried “a substantial
mandatory minimum.” See 18 U.S.C. § 924(c). Williams fur-
ther conceded that he was testifying for the government to get
his “time cut” on the charge that he pled guilty to—conspir-
acy to distribute at least a kilogram of heroin—which carried
“substantial penalties” and a “substantial mandatory mini-
mum.” On top of that, Williams admitted that the government
never filed a sentencing enhancement against him even
though he had two qualifying prior convictions. See 21 U.S.C.
§ 851.
    For his part, Naylor testified on cross-examination that the
government agreed to dismiss a § 924(c) count against him
carrying a “substantial mandatory minimum.” The govern-
ment also agreed not to file an applicable sentencing enhance-
ment on the charge that Naylor pled guilty to—possession
with intent to distribute heroin—which would have resulted
in “even longer punishment in prison.” Naylor added that he
was hoping to receive “a further sentence reduction” for tes-
tifying against the defendants. He understood that the gov-
ernment could move for such a reduction based on its evalu-
ation of his trial testimony.
    This testimony shows that Harris could, and did, question
the cooperators at length about their potential biases and mo-
tives to lie. As such, we review for abuse of discretion. Trent,
863 F.3d at 704. To decide if the court abused its discretion, we
ask “whether the jury had suﬃcient information to make a
discriminating appraisal of the witness’s motives and biases.”
Id. at 706 (quoting Sanders, 708 F.3d at 991). The district court
gave Harris wide latitude to cross-examine the cooperators
Nos. 20-1236 & 20-2234                                          25

about everything except the exact sentences they hoped to
avoid by testifying for the government. As set forth above,
Harris thoroughly probed the cooperators’ biases and mo-
tives to lie. Both witnesses admitted that they faced significant
sentences that they hoped the government would ask the
court to reduce in light of their testimony. As in Trent, the
court “did not err, let alone abuse its discretion,” in keeping
the cooperators exact sentences oﬀ limits. Id.
    Harris counters that Trent and Hunter should not apply
here because Williams and Naylor were not codefendants in
the defendants’ case. But what matters under Trent and
Hunter is that the jury might infer the defendants’ potential
sentences from the cooperators’ potential sentences. See Trent,
863 F.3d at 705; Hunter, 932 F.3d at 619. Here, Williams was
charged separately, but he faced the same exact charge as the
defendants: conspiracy to distribute at least a kilogram of her-
oin. See 21 U.S.C. §§ 841(b)(1)(a), 846. Indeed, the district court
instructed the jury that Williams “was involved in and has
pled guilty to charges relating to the crime the defendants are
charged with committing.” Given the identical nature of Wil-
liams’s charges and the defendants’ charges, the court was
well within its discretion to limit Harris’s cross-examination
of Williams.
    Naylor, on the other hand, pled guilty to possession with
intent to distribute heroin, see 21 U.S.C. § 841(a)(1), a diﬀerent
crime corresponding to a lower mandatory minimum. The
district court acknowledged this diﬀerence, but explained its
decision to nonetheless limit Harris’s cross-examination of
Naylor:
   While it’s not the exact same charge, it is under the
   same statute. I believe the oﬀense to which he pled
26                                       Nos. 20-1236 & 20-2234

     guilty to constitutes one of the lesser includeds that the
     Court intends to give, and the plea agreement does, in
     fact, state that there’s a mandatory minimum of five
     years, which I think would give some insight into what
     these defendants might be looking at if convicted of
     these charges.
    The court carefully and permissibly exercised its discre-
tion. We acknowledge, as we did in Hunter, that sharing spe-
cific sentencing information with the jury is of concern when
the cooperators and defendants face the same or similar
charges. Hunter, 932 F.3d at 619. Here, though, the court rea-
sonably concluded that the charge to which Naylor pled
guilty was similar enough to the defendants’ charges that the
jury might try to “deduce or infer the sentences facing the
similarly-charged defendants” from information about
Naylor’s sentence. Id. On these facts, we see no abuse of dis-
cretion.
    We thus aﬃrm the district court’s limits on Harris’s cross-
examination of Williams and Naylor. Harris’s only other ar-
gument on this score is a perfunctory and conclusory plea for
us to overrule Trent and Hunter. This argument is waived.
Puﬀer v. Allstate Ins. Co., 675 F.3d 709, 718 (7th Cir. 2012)
(“[E]ven arguments that have been raised may still be waived
on appeal if they are underdeveloped, conclusory, or unsup-
ported by law.”).
D. Harris’s Sentence
    Finally, Harris argues that his sentence of 262 months’ im-
prisonment is substantively unreasonable because it is 22
months longer than Gibson’s, even though Gibson was an
“organizer or leader” of the drug-traﬃcking scheme whereas
Nos. 20-1236 & 20-2234                                        27

Harris was only a “manager or supervisor.” See USSG § 3B1.1
(requiring a four-level enhancement for organizers or leaders
and a three-level enhancement for managers or supervisors).
    We review the reasonableness of a sentence for abuse of
discretion. Castro-Aguirre, 983 F.3d at 943. A below-Guide-
lines sentence is presumptively reasonable. Id. at 944. “In-
deed, we have never ‘deemed a below-range sentence to be
unreasonably high.’” Id. (quoting United States v. Brown, 932
F.3d 1011, 1019 (7th Cir. 2019)).
    The district court did not abuse its discretion in sentencing
Harris to 262 months’ imprisonment—a sentence that fell
nearly 100 months below the low end of the advisory Guide-
lines range of 360 months to life. As Harris points out, the dis-
trict court had to consider, among other sentencing factors,
“the need to avoid unwarranted sentence disparities among
defendants with similar records who have been found guilty
of similar conduct.” 18 U.S.C. § 3553(a)(6). And it did so. At
Harris’s sentencing, the court expressly considered the need
to avoid an unwarranted sentencing disparity between Harris
and Gibson, who had similar roles in the conspiracy and iden-
tical Guidelines ranges. The court explained, however, why a
sentencing disparity between Gibson and Harris was not, in
fact, “unwarranted.” At 47, Gibson was nine years older than
Harris. Gibson was also serving a 12-year consecutive sen-
tence for a § 924(c) conviction in another jurisdiction. Those
factors influenced Gibson’s likelihood of reoﬀending upon re-
lease, which is another sentencing factor. See § 3553(a)(2)(C);
see also Dean v. United States, 137 S. Ct. 1170, 1176 (2017). The
same recidivism calculus did not apply to Harris, who was
younger and not facing a long consecutive sentence in another
case.
28                                      Nos. 20-1236 & 20-2234

   A district court has broad discretion to balance the
§ 3553(a) factors. United States v. Warner, 792 F.3d 847, 855 (7th
Cir. 2015). The court’s reasoned decision to give Harris 22
months more than Gibson was well within the range of rea-
sonable sentences.
                        III. Conclusion
   For these reasons, we aﬃrm the defendants’ convictions
and sentences.