UNITED STATES OF AMERICA, PETITIONER V. ALBERTO ANTONIO LEON, ET

   AL.

   No. 82-1771

   In the Supreme Court of the United States

   October Term, 1983

   On Writ of Certiorari to the United States Court of Appeals for the
Ninth Circuit

   Reply Brief for the United States

   1.a. For the most part, respondents and the amici curiae supporting
them counter our arguments in favor of a "reasonable mistake"
exception to the exclusionary rule with dire predictions about the
demise of the Fourth Amendment and the values it protects.

   Respondents and their amici have largely chosen to ignore the fact
that continued application of the exclusionary rule in the class of
cases to which a reasonable mistake exception would apply -- i.e.,
those near the often indistinct boundary between good police work and
impropriety -- is as likely to deter the police from properly
performing their job as it is to encourage compliance with the Fourth
Amendment.  Indeed, one of the most substantial group of cases to
which a "reasonable mistake" exception would often apply is, we
submit, cases in which the prosecution should have prevailed on the
merits but in which lower courts erroneously find a Fourth Amendment
violation.  See, e.g., Gov't Br. 51 n.16.  This Court cannot correct
every such error itself, particularly in cases like the present one,
in which the underlying Fourth Amendment issue is entirely fact-bound.
 Adoption of a reasonable mistake exception should therefore serve to
return the balance where it properly belongs by eliminating, the
over-deterrence now imposed by unrelenting application of the
exclusionary rule.  /1/ Any fair reading of our opening brief should
dispel respondents' exaggerated concerns;  indeed, as we previously
noted (Br. 63-64, 76-77), the common-sense modification of the
exclusionary rule that we propose should serve to strengthen the
substance of the Fourth Amendment.

   b. Respondents and their amici nevertheless argue that our proposal
is in reality a direct attack on the Warrant Clause itself, and that a
reasonable mistake exception to the exclusionary rule would, in the
wake of this Court's decision in Illinois v. Gates, No. 81-430 (June
8, 1983), represent a "double dilution" of the Fourth Amendment's
probable cause standard.  In the same vein, respondents and the amici
supporting them argue that it is logically impossible to defend a
reasonable mistake exception to the exclusionary rule because the
result would be the creation of a category of "reasonably unreasonable
search(es)" (see, e.g., Leon Br. 54-57).  Neither argument is
persuasive.

   Respondents' "double dilution" argument is based on a faulty
underlying premise.  The first level of "dilution," according to
respondents, is the definition of probable cause articulated by this
Court in Gates.  Respondents and others may well believe that Gates
"diluted" the definition of probable cause, but the Court itself did
not.  Instead, the Court stated that Gates's "totality of the
circumstances approach is far more consistent with our prior treatment
of probable cause than is any rigid demand that specific 'tests' be
satisfied by every informant's tip." Gates, slip op. 15-17 (emphasis
added;  footnote omitted).  Indeed, the Court traced its reiteration
of probable cause as a "'practical, non-technical conception'" back to
its 1949 decision in Brinegar v. United States, 338 U.S. 160, 176.
Gates, slip op. 16.  Thus, respondents' first level of "dilution"
involves no dilution at all but instead represents a reaffirmation of
what the Court has long understood the concept of probable cause to
entail.

   Respondents' second level of "dilution" stems from their perception
that we are asking the Court to approve warrants issued on less than
probable cause, even as defined in Gates.  That is not the case.
Quite clearly, we could not and do not ask the Court to disregard the
plain language of the Warrant Clause.  Instead, our proposal only
recognizes the obvious:  satisfaction of the standard for probable
cause will usually turn on fact-bound judgments that must be made on a
case-by-case basis, and there will always be cases in which reviewing
courts determine that the facts fall slightly short of meeting that
standard even though reasonable persons could as easily have reached
the opposite conclusion.  Indeed, in the category of cases to which a
reasonable mistake exception would apply, there will ordinarily be
room for considerable difference of opinion concerning the
reasonableness of the challenged practice.  Respondents' argument
reduces to the proposition that in any case in which this Court
divides five to four on the question of probable cause, either five or
four Justices of this Court are "unreasonable" because they came to
the "wrong" conclusion.  Obviously, it is untenable to suggest that in
this area of the law there can be only one "reasonable" answer,
notwithstanding the fact that there can be only one final answer.

   We thus ask the Court not to alter or "dilute" the Warrant Clause,
but to recognize the distinction between the wrong and the remedy -- a
distinction ignored by respondents in their "double dilution" and
"reasonably unreasonable searches" arguments.  It does not follow that
a search that is "unreasonable" in the sense that five Justices of
this Court have said it is must be met with a rigid remedial
prescription that may be unreasonably disproportionate to the
violation.  Rather, having found that a particular search or seizure
was in violation of the Fourth Amendment, and therefore "unreasonable"
as a matter of substantive law, a court should undertake a separate
inquiry into the reasonableness of applying the exclusionary rule.
See pages 17, infra.  This is a distinct facet of "reasonableness"
that focuses not on the substance of the Fourth Amendment, but instead
on the purposes to be served by the exclusionary rule.  That there is
no logical inconsistency in this approach is demonstrated by the
Court's decisions in cases such as United States v. Havens, 446 U.S.
620 (1980);  United States v. Ceccolini, 435 U.S. 268 (1978);  United
States v. Calandra, 414 U.S. 338 (1974);  and Alderman v. United
States, 394 U.S. 165 (1969) (see the discussion at pages 34-38 of our
opening brief).

   2. The modification of the exclusionary rule that we propose would
in no way undermine the existing incentives for police adherence to
settled Fourth Amendment norms.  Respondent Leon's argument to the
contrary (Br. 37-39;  see also Sanchez, et al. Br. 17-18 & n.7) is
untenable.  Leon contends (Br. 37-39) that a number of this Court's
prior cases would have been decided differently had the Court
previously employed a reasonable mistake exception to the exclusionary
rule and that those cases would now be "effectively overruled" (id. at
38).  While the first observation may well be correct (see Gates, slip
op. 11 n.12 (White, J., concurring)), the second is utterly without
support.  On the contrary, our proposal does not require this Court to
overrule any of its prior precedents.  The cases to which respondent
Leon refers already have been decided, and, regardless of what the
result in any particular case might have been had the Court employed a
"reasonable mistake" approach, those decisions now represent
established Fourth Amendment law.  Under our proposal, the
exclusionary rule would continue to apply in essentially unchanged
form to evidence seized in clear violation of settled constitutional
principles;  thus, whatever deterrence the rule now provides would
continue largely undiminished.

   3. Central to respondents' argument is the contention that adoption
of a reasonable mistake exception to the exclusionary rule would
"freeze" Fourth Amendment jurisprudence in its present state because
the courts would be thereafter disabled from adjudicating new or
unsettled issues by the likelihood that a disposition of the issue in
the defendant's favor would nevertheless not lead to reversal of his
conviction.  Jurisprudential principles rooted in Article III thus
would, it is asserted, preclude the courts from deciding substantive
constitutional search and seizure issues, and the exclusionary rule
would no longer provide a vehicle for new constitutional adjudications
to guide future behavior of law enforcement officials.  This line of
argument is multiply flawed.

   a. There is no serious dispute that the fundamental justification
for the exclusionary rule resides in its hoped-for effect of securing
governmental obedience to the dictates of the Fourth Amendment as
explicated by the courts.  There is, however, a significant difference
between that purpose and the purpose ascribed to the rule by
respondents and others opposing our position, viz., to create for the
courts opportunities to render new constitutional adjudications.  Any
such justification for the exclusionary rule is surely a classic
example of the tail wagging the dog.  To anyone but a lawyer, and even
to many lawyers, the idea that the exclusionary rule must be retained
in its present form in order to perpetuate opportunities for
litigation must seem absurd.  Preserving a rule of evidence that is as
demonstrably costly and ineffective as the exclusionary rule (in the
class of cases here considered) for the purpose of assuring a
continued flow of litigation is surely beyond the proper limits of the
judicial function.  Indeed, it is particularly ironic for respondents
to support their argument that the exclusionary rule is needed to
provide constitutional cases for the courts to adjudicate by reliance
on this Court's cases cautioning against the unnecessary resolution of
constitutional issues (Leon Br. 26 & n.40;  Sanchez, et al. Br. 27).

   b. Even if respondents and their amici were correct in their
contention that adoption of a reasonable mistake exception to the
exclusionary rule would deprive suppression motions of their status as
vehicles for resolution of heretofore unsettled issues of substantive
Fourth Amendment law (a proposition refuted in our opening brief (at
83-86 & n.52) and elaborated upon below), many of the more important
and recurring issues of this nature can be resolved in other types of
judicial proceedings.  See Gates, slip op. 20-21 & n.19 (White, J.,
concurring).  For example, although there are no doubt limits on the
circumstances in which such actions will lie (e.g., Rizzo v. Goode,
423 U.S. 362 (1976)), a pattern or practice of official conduct that
is alleged to violate Fourth Amendment rights can often be challenged
by an aggrieved individual in a suit for declaratory and injunctive
relief.  The warrant/subpoena issue decided by the Court in Zurcher v.
Stanford Daily, 436 U.S. 547 (1978), is one example of such
litigation.  The "border search" practice condemned in Torres v.
Puerto Rico, 442 U.S. 465 (1979), is another issue that unquestionably
could have been resolved as well in an action for declaratory relief
by a regular traveler to Puerto Rico who was subjected to such
searches upon arrival.  The same is true of the checkpoint stop issue
resolved in United States v. Martinez-Fuerte, 428 U.S. 543 (1976), the
validity of suspicionless boat stops for document inspections in
inland waters upheld in United States v. Villamonte-Marquez, No.
81-1350 (June 17, 1983), and the constitutionality of INS factory
inspection procedures, now before the Court in INS v. Delgado, cert.
granted, No. 82-1271 (Apr. 25, 1983).

   It is true that not every arguably unconstitutional practice will
be amenable to review in a suit for declaratory or injunctive relief,
for such suits require a proper plaintiff.  See City of Los Angeles v.
Lyons, No. 81-1064 (Apr. 20, 1983).  But even if no individual may be
sufficiently exposed to risk of future injury to bring an action for
declaratory or injunctive relief, damages actions against
municipalities under 42 U.S.C. (Supp. V) 1983 also afford an avenue
for substantive judicial review of the validity of many questionable
police practices.  Although a municipality is not liable under Section
1983 on a theory of respondeat superior, local governing bodies are
subject to suit for constitutional torts resulting from implementation
of local ordinances, regulations, policies, or even customary
practices.  Monell v. Department of Social Services, 436 U.S. 658
(1978).  And by virtue of the holding in Owen v. City of Independence,
445 U.S. 622 (1980), such entities enjoy no good faith defense that
might (under respondents' theory) impede resolution of the substantive
constitutional issue.  Consequently, for example, the validity of the
policy of a local police force to make random, suspicionless stops of
automobiles to enforce motor vehicle licensing and registration laws,
decided by this Court in Delaware v. Prouse, 440 U.S. 648 (1979),
could as well have been decided in a damages action by a motorist who
had been unlawfully stopped (without even the cost of letting a single
guilty offender go free).  /2/ Similarly, the validity of police
automobile inventory practices, passed upon in South Dakota v.
Opperman, 428 U.S. 364 (1976), could instead have been adjudicated in
a civil action.  The validity of the "chokehold" practice challenged
in City of Los Angeles v. Lyons, supra, likewise could be resolved in
an action for damages (see Lyons, slip op. 9), as could the
statutorily-authorized suspicionless "pat-downs" invalidated in Ybarra
v. Illinois, 444 U.S. 85 (1979).

   Finally, it may be predicted with some assurance that even if this
Court modifies the exclusionary rule as we have proposed, a number of
state courts will decline to follow its lead as a matter of state law
and will continue to suppress evidence in state trials for any Fourth
Amendment violation.  This Court should therefore still have available
a sufficient supply of state criminal cases in which to resolve
important, unsettled questions of Fourth Amendment law.

   Perhaps the various avenues for substantive constitutional
adjudication discussed above would not provide as fast and furious a
supply of Fourth Amendment issues as does the present form of the
exclusionary rule, but there is no basis for concluding that
important, recurrent issues need go too long unresolved even if
modification of the exclusionary rule were to diminish substantially
the number of criminal cases in which resolution of such issues is
essential.  Accordingly, there need be no fear that Fourth Amendment
law will become "frozen" in its current state.  /3/

   c. In any event, as noted in our opening brief (at 83-86 & n.52),
there is no jurisdictional bar to a court's deciding a question of
Fourth Amendment law even if the outcome of the case may in the end be
controlled by application of a reasonable mistake exception to the
exclusionary rule.  Respondents' reliance on Article III is misplaced.
 /4/ At bottom, respondents' argument is that courts are
constitutionally required to limit their opinions to the bare minimum
necessary to make a dispositive judgment of the particular case.  This
position reads far more into Article III than this Court has ever
suggested.  Nothing in Article III prevents a court from analyzing the
issues presented by a suppression motion in whatever order it deems
most appropriate (see the discussion at pages 85-86 of our opening
brief).

   Conceptually, the situation here is no different from countless
other situations in which a claimant must clear more than one hurdle
before establishing his entitlement to relief.  For example, nothing
in Article III requires a court to decide a plaintiff's entitlement to
damages before it decides the question of liability, even though a
holding that the plaintiff is entitled to no damages would render
decision of the liability issue unnecessary.  Logically, a court would
almost always determine liability before it considers relief, and the
situation here would be no different.  Respondents also ignore the
possibility that the Fourth Amendment issue is potentially dispositive
of the entire controversy if it is resolved in the prosecution's favor
(making it unnecessary to consider the applicability of a reasonable
mistake exception).  Instead, they apparently would require a court to
organize its consideration of a case backwards, looking always to find
any affirmative derense that might defeat relief before examining the
substance of the claim.  /5/

   This Court has never suggested that such a practice is required.
Indeed, in O'Connor v. Donaldson, 422 U.S. 563 (1975), the Court
followed precisely the procedure that, according to respondents, would
violate Article III.  In that case, the Court first held that
respondent had been unconstitutionally deprived of his right to
liberty through confinement in a mental institution (422 U.S. at
573-576).  The Court then remanded the case for the court of appeals
to consider petitioner's claim of a good-faith immunity defense in
light of the intervening decision in Wood v. Strickland, 420 U.S. 308
(1975).  Had the Court accepted respondents' view of Article III, it
necessarily would have remanded the case without deciding the Fifth
Amendment claim.

   Respondents' error lies in confusing the case or controversy
requirement of Article III with the juris-prudential policy of this
Court to avoid unnecessary constitutional decisions.  That
long-established policy is beyond reproach, and we do not suggest that
the Court depart from it as a general rule.  But neither should the
Court turn a prudential guideline into rigid constitutional doctrine
(cf. Hagans v. Lavine, 415 U.S. 528, 546 (1974) ("(t)he doctrine is
not ironclad * * *")).  When sound reasons exist for departing from
the general policy, Article III imposes no barrier against doing so.
Thus, although courts clearly are not compelled to decide
constitutional questions that may not dispose of a case, there is no
error in doing so, especially when the "questions are otherwise
properly before (the court) and may be resolved without imposing * * *
additional litigative burdens." Davis v. Passman, 442 U.S. 228, 236
n.11 (1979).

   Cases raising novel or unresolved but important and recurrent
search and seizure questions might well present appropriate situations
for the courts to depart from their normal practice, because the
prudential reasons for avoiding unnecessary constitutional decisions
would be outweighed by a perceived need to provide law enforcement
officers with guidance concerning lawful conduct.  The constitutional
ruling in such cases would not be a prohibited advisory opinion
because, as noted in our opening brief (at 85), it is clear that the
defendant would be presenting a live controversy concerning the
requirements of the Fourth Amendment.  The end result simply would be
that, notwithstanding the constitutional violation, the defendant
would not be entitled to the remedy of suppression.  /6/

   4. Respondents argue (Sanchez, et al. Br. 28-29) that a reasonable
mistake exception will halt the development of "bright-line" rules to
guide police conduct.  We have just shown that respondents' fear that
Fourth Amendment adjudications will cease is unfounded.  But even
assuming the correctness of respondents' underlying premise, it is
clear that bright-line rules cannot possibly be devised for every
Fourth Amendment situation confronting law enforcement officials in
the performance of their duties.  As one commentator has observed
(Ashdown, Good Faith, The Exclusionary Remedy, and Rule-Oriented
Adjudication in the Criminal Process, 24 Wm. & Mary L. Rev. 335, 365
(1983)):

      The problem * * * is an inherent inability to achieve an
      adequate level of irradiation for the police to consistently
      follow and for the courts to effectively utilize.  Fourth
      Amendment encounters between the police and the public are
      simply too numerous and too varied to be subject to standardized
      procedures that will always dictate the appropriate police
      response.  Because of this variety and diversity, attempts to
      draft bright-line rules have proved unsuccessful.  Such rules
      provide some guidance but are incapable of addressing in advance
      all the factual situations that police may encounter.

   The instant case offers a clear example of the impossibility of
devising bright-line rules for every situation.  Respondents have not
even attempted to articulate any rule that would have told Officer
Rombach what additional information he should have obtained before
applying for a warrant in this case (assuming, arguendo, that the
lower courts correctly held that he had not already obtained
sufficient information to establish probable cause).  Thus, it is in
fact-bound disputes such as the present one that the courts are least
able to guide officers in the daily performance of their duties.  As
the Court observed in Gates, slip op. 23 n.11, "(t)here are so many
variables in the probable cause equation that one determination will
seldom be a useful 'precedent' for another." See also slip op. 17.
Moreover, it is in these same cases that the risk of erroneous
suppression rulings is at its greatest, because it is inevitable that
reasonable persons will differ as to the sufficiency of a given
quantum of information when the question is a close one.  Thus,
however desirable the development of bright-line rules may be, such
rules provide no solution to cases such as this.

   5. Respondents contend (Leon Br. 57-58;  Sanchez, et al. Br. 11-16)
that the exclusionary rule is a constitutionally required remedy for
Fourth Amendment violations.  Respondents Sanchez, et al. argue (Br.
11-14) that the exclusionary rule is required by the Fifth Amendment
as well, relying on this Court's decision in Boyd v. United States,
116 U.S. 616 (1886), and Justice Black's concurring opinion in Mapp v.
Ohio, 367 U.S. 643, 662 (1961) (Black J., concurring).  Neither
argument is correct.

   a. Respondents' Fifth Amendment argument completely overlooks this
Court's decision in Andresen v. Maryland, 427 U.S. 463 (1976).  There,
the Court squarely rejected the notion that the broad language in Boyd
and subsequent cases discussing the relationship between the Fourth
and Fifth Amendments compelled suppression of petitioner's business
records (427 U.S. at 472).  The Court explained (id. at 473-474) that:

         This case thus falls within the principle stated by Mr.
      Justice Holmes:  "A party is privileged from producing the
      evidence but not from its production." Johnson v. United States,
      228 U.S. 457, 458 (1913).  This principle recognizes that the
      protection afforded by the Self-Incrimination Clause of the
      Fifth Amendment "adheres basically to the person, not to
      information that may incriminate him." Couch v. United States,
      409 U.S., at 328.  Thus, although the Fifth Amendment may
      protect an individual from complying with a subpoena for the
      production of his personal records in his possession because the
      very act of production may constitute a compulsory
      authentication of incriminating information, see Fisher v.
      United States, supra, a seizure of the same materials by law
      enforcement officers differs in a crucial respect -- the
      individual against whom the search is directed is not required
      to aid in the discovery, production, or authentication of
      incriminating evidence.

   Here, too, because respondents were "not compelled to testify in
any manner" (Andresen, 427 U.S. at 477), the Fifth Amendment privilege
against self-incrimination is simply not implicated.  See also Wilson,
The Origin and Development of the Federal Rule of Exclusion, 18 Wake
Forest Law Rev. 1073, 1096-1101 (1982).

   b. Respondents' argument that the exclusionary rule is required by
the Fourth Amendment fares no better.  As we noted in our opening
brief (at 31), the Court has never held that the rule is
constitutionally required.  Respondents' argument to the contrary
depends on the "personal right" theory (see Leon Br. 57-58) -- a
doctrine long ago repudiated by this Court.  See, e.g., United States
v. Calandra, 414 U.S. 338, 348 (1974) (exclusionary rule not "a
personal constitutional right of the party aggrieved").  Respondents
and their amici dismiss Calandra and other cases rejecting the
personal right theory on the basis that those cases involved the
"collateral" use of illegally obtained evidence, rather than the use
of such evidence as part of the government's case-in-chief against a
defendant who has himself been the victim of an unlawful search or
seizure.  /7/ Only last Term, however, the Court reiterated its
rejection of the personal right theory (Gates, slip op. 8) without in
any way suggesting that the rejection was limited to "collateral" uses
of illegally obtained evidence.  Instead, the Court observed, in words
of general applicability, that "(t)he question whether the
exclusionary rule's remedy is appropriate in a particular context has
long been regarded as an issue separate from the question whether the
Fourth Amendment rights of the party seeking to invoke the rule were
violated by police conduct." Ibid.  The Court made the same point in
United States v. Janis, 428 U.S. 433, 443 (1976) (footnote omitted):

      (The) comparatively late judicial creation of a Fourth Amendment
      exclusionary rule is not particularly surprising.  In contrast
      to the Fifth Amendment's direct command against the admission of
      compelled testimony, the issue of admissibility of evidence
      obtained in violation of the Fourth Amendment is determined
      after, and apart from, the violation.

   See also Scott v. United States, 436 U.S. 128, 135-137 (1978);
Wilkey, Constitutional Alternatives to the Exclusionary Rule, 23 S.
Tex. L.J. 531, 542-557 (1982).

   In our view, therefore, the nature of the proceeding, though
relevant, is not a controlling inquiry;  rather, the question is
whether the "remedial objectives * * * (of the exclusionary rule will
be) efficaciously served." Calandra, 414 U.S. at 348.  While it may be
conceded, for purposes of argument, that those objectives are most
likely to be served in the context of the main criminal trial itself,
nevertheless, as we demonstrated in our opening brief, they are not
sufficiently served in situations in which the police cannot
reasonably be expected to have known that their conduct would later be
declared unlawful.  Assuming, arguendo, that the Constitution
contemplates a remedy for Fourth Amendment violations, respondents
have nevertheless failed to provide any support for the proposition
that the Constitution requires an ineffective remedy.  The Court's
decisions limiting the suppression remedy to those cases in which it
can be expected to achieve its intended result are thus fully
consistent with the Constitution, as is our proposal for a reasonable
mistake modification to the exclusionary rule.

   6. Citing various empirical studies, respondents contend that the
exclusionary rule actually frees very few criminal defendants
(Sanchez, et al. Br. 60-64;  Leon Br. 43-53).  /8/ In the final
analysis, however, the conflicting empirical data would seem to be of
little benefit to the Court;  it is more probable, as Justice White
noted in his concurrence in Gates (slip op. 12), that "(w)e will never
know how many guilty defendants go free as a result of the rule's
operation." But this Court's own experience would seem to belie
respondents' minimization of the impact of the exclusionary rule.  As
we noted in our opening brief (at 51 n.16), last Term alone this Court
reversed seven lower court decisions that had invalidated searches or
seizures on Fourth Amendment grounds.  If that many cases are affected
at the apex of the criminal justice pyramid, it simply is not credible
to assume that the rule's impact in the lower courts is insignificant.

   Assuming for the sake of argument, however, that respondents are
correct in their assessment of the rule's impact, their vigorous
opposition to our proposal can be explained only by a desire to retain
the windfall benefits of the rule for the few guilty defendants who
are fortunate enough to invoke it successfully.  We have previously
shown that the rule would remain unchanged in the case of clear
violations of the Fourth Amendment, and respondents have utterly
failed to demonstrate how the rule's deterrent purposes can be
achieved when it is applied to conduct that the police could not
reasonably be expected to have known was illegal.  Thus, retention of
the rule in the class of cases here under consideration is costly no
matter how few guilty defendants escape conviction because no
countervailing benefits are obtained for the criminal justice system;
on the contrary, the system is severely taxed by having to devote
significant amounts of time and resources to Fourth Amendment issues
of only marginal significance (see Gov't Br. 74-75).

   7. Respondents' apocalyptic prediction that creation of a
reasonable mistake exception to the exclusionary rule would result in
the wholesale abdication by magistrates of their duty to make a
reasoned decision on every application for a search warrant is riddled
with contradictions.  On the one hand, respondent Leon argues, in
effect, that most magistrates are already so incompetent that they
cannot be trusted to perform their job (Br. 10-13).  On the other
hand, he argues (Br. 13-16) that they can be controlled through
judicial review, which he erroneously assumes would cease if the Court
were to adopt a reasonable mistake exception.  But if magistrates are
already failing to perform their job, the logical conclusion to be
drawn is that they are simply unresponsive to the suppression
sanction, and its continued application to them therefore serves no
purpose.  Similarly, respondent Leon argues (Br. 18) that virtually
all magistrates are "rubber stamps" under the current system, and at
the same time contends (Br. 22) that a reasonable mistake exception
would encourage "magistrate shopping." If respondent Leon's view of
the current system is at all accurate, there would be no need for the
police to resort to "magistrate shopping" in the future.

   In our submission, respondents' dismal picture of magistrates'
current performance is greatly exaggerated, /9/ but, in any event,
respondents have offered no reason to believe that a reasonable
mistake exception would create any new incentive for magistrates to be
lax or remiss in their duties.  Moreover, respondents ignore the fact
that magistrates have no partisan stake in the outcome of a
prosecution (see Gov't Br. 58-60).  To the extent that magistrates are
trained professionals (e.g., lawyers or judges), they may be expected
to respond to the judicial guidance supplied by appellate review
which, as we have shown, would continue to be available in appropriate
cases.  Maintaining the additional sanction of suppression, however,
is simply overkill;  it cannot "deter" those who have no stake in
being deterred.  Non-lawyer magistrates, on the other hand, are even
less likely to be influenced by the exclusionary rule.  Not only do
they lack any stake in the prosecution, but they also lack the
professional background necessary to make them responsive to appellate
oversight.  Granting, then, that the use of non-lawyer magistrates may
well be a matter of concern for the criminal justice system, the fact
remains that suppression is an inappropriate response to the problem.
/10/ It cannot be shown to serve the purpose of improving magistrates'
performance, while at the same time it penalizes the police for
mistakes they did not make.  In short, the problem of poor performance
by some magistrates will not be solved by continued application of the
exclusionary rule to the type of case under consideration here.

   8. We clearly stated in our opening brief (at 78-81) that the
reasonable mistake exception should be grounded in objective
reasonableness and that the subjective intent of the searching officer
would be irrelevant (except, perhaps, in those rare cases in which a
warrant was procured in bad faith or on the basis of material
misrepresentations (see Franks v. Delaware, 438 U.S. 154 (1978)).
Nevertheless, respondents persist in the argument that our proposal
would necessarily entail a subjective component as well, apparently
for the dual purpose of enabling them to present the Court with the
spectre of unwieldy judicial proceedings and repetition of the canard
that our proposal would "place a premium on police ignorance." Neither
proposition has merit.

   Respondents themselves acknowledge that a subjective inquiry would
be both awkward and unproductive.  See Sanchez, et al. Br. 46.  It is
precisely for these reasons that we would eschew the subjective
inquiry altogether.  The objective assessment that we propose would be
conducted in much the same manner as substantive Fourth Amendment
questions are now decided and would be no more difficult than what is
required in good-faith immunity cases under Harlow v. Fitzgerald, 457
U.S. 800 (1982).  Asking an officer "to explain why he acted
unconstitutionally" (Sanchez, et al. Br. 46) would be neither
necessary nor appropriate.  Rather, the determination of objective
reasonableness would be essentially a question of law, in which a
court need determine only whether an officer's conduct departed unduly
from established Fourth Amendment principles.  /11/

   The contention that a reasonable mistake exception would put a
premium on police ignorance is a strawman;  by definition, a
reasonably well-trained officer must have more than a passing
acquaintance with Fourth Amendment law.  For the same reason, there
would be no incentive for police departments to abandon training
programs, or for individual officers deliberately to engage in
searches of dubious legality, because to do so would deprive them of
the benefits of an objective reasonable mistake exception.  So too,
the incentives for internal review of warrant applications would
continue unchanged.  On the federal level, FBI and DEA agents are
required to obtain the approval of an Assistant United States Attorney
before applying for a search warrant, /12/ and that policy would not
be abandoned if a reasonable mistake exception were adopted.  Indeed,
any law enforcement officer or department that sanctioned a shift from
"'what does the fourth amendment require?' to 'what will the courts
allow me to get away with?'" (Stewart, The Road to Mapp v. Ohio and
Beyond:  The Origins, Development and Future of the Exclusionary Rule
in Search-and-Seizure Cases, 83 Colum. L. Rev. 1365, 1403 (1983)
(footnote omitted)) would simply be increasing the likelihood of
suppression.  Assuming the validity of the deterrence rationale by
which the exclusionary rule is justified, there is thus no basis for
supposing that a reasonable mistake exception would encourage Fourth
Amendment violations.

   In short, it is beyond dispute that police training in the
requirements of the Fourth Amendment has improved markedly since Weeks
and Mapp were decided.  But even the best-designed training programs
can do no more than educate officers as to the extant principles of
law.  Hypothetical answers to unsettled questions as to which
reasonable judges could differ cannot realistically serve as a guide
for police conduct.  Once the questions have been answered, however,
the reasonable mistake exception we propose will increase the
incentives for police departments to disseminate new legal rulings as
rapidly as possible.  Far from placing a premium on ignorance, an
exception that is keyed to the reasonably well-trained police officer
places a premium on reasonableness and on training.

   9. Respondents Sanchez, et al. argue (Br. 48-50) that any
modification of the exclusionary rule should be left to Congress.
While legislative action would indeed be an appropriate and welcome
response to the increasingly widespread recognition that the rule
requires modification, this Court need not wait for Congress to act.
More than a decade ago, the Chief Justice urged congressional action
(Bivens v. Six Unknown Named Agents of the Federal Bureau of
Narcotics, 403 U.S. 388, 421 (1971) (Burger, C.J., dissenting)), but
to date Congress has not responded.  The speculative possibility that
legislation might someday be enacted should not deter the Court from
resolving the important question presented by this case, particularly
when the issue is the proper application of a rule created by this
Court itself.

   10. Finally, respondent Leon argues (Br. 70-73) that any reasonable
mistake modification adopted by this Court should not apply to him
because "no reasonable California police officer could conclude, under
the prevailing articulated legal standards, that probable cause to
search Mr. Leon's house had been made out" (id. at 70 (footnote
omitted)).  Notably, the other respondents make no comparable
arguments.  Respondent Leon is able to make the argument only by
reliance on a rigid reading of the now-discarded Aguilar-Spinelli
test;  /13/ his argument that no reasonable officer could have
concluded that the "totality of the circumstances" established
probable cause flies in the face of common-sense experience in
narcotics cases.  As Judge Kennedy observed in dissent, the officers'
month-long investigation in this case revealed a pattern of conduct
that "was inconsistent with any explanation other than illegal drug
activity" (Pet. App. 5a).  /14/

   For the foregoing reasons, as well as those stated in our opening
brief, the judgment of the court of appeals should be reversed.

   Respectfully submitted.

   REX E. LEE

      Solicitor General

   JANUARY 1984

   /1/ Respondents may well be correct that the prosecution should
generally prevail without benefit of a reasonable mistake exception
because the strong deference accorded to magistrates' determinations
of probable cause (see, e.g., Illinois v. Gates, No. 81-430 (June 8,
1983), slip op. 21-22, 23-24) is, at least in certain types of cases,
the functional equivalent of our current proposal (see Leon Br. 9;
Sanchez, et al. Br. 33-37).  Yet respondents argue that this is so
only in the wake of Gates.  They conveniently ignore the fact that
Gates's rule of deference is not new, but instead merely reaffirms
United States v. Ventresca, 380 U.S. 102 (1965), and Jones v. United
States, 362 U.S. 257 (1960).  The Court found in Gates, however, that
many lower courts had not been applying the proper standard of review
(Gates, slip op. 19 & n.9, 21), even though it had been settled for
more than 20 years.  It remains to be seen whether lower courts will
pay greater attention to Gates's reaffirmation of settled law than
they did to Jones and Ventresca.  (The Ninth Circuit, for example, has
expressed the view (totally unfounded, in our submission) that Gates's
prohibition against de novo review of magistrates' determinations of
probable cause may be limited to cases involving an informant's tip.
See United States v. Rubio, No. 80-1577 (9th Cir. Dec. 20, 1983), slip
op. 10-11.) It is worth noting, however, that there is a certain irony
in respondents' vigorous opposition to a proposal they claim the Court
has already effectively adopted in Gates.

   In any event, a deferential standard of review is an incomplete
substitute for the entire range of cases to which a reasonable mistake
exception would apply.  While the number of such cases has not, and
probably cannot, be verified, their existence is undeniable.  Gates's
rule of deference does not address, for example, the situation
presented in cases like Massachusetts v. Sheppard, cert. granted, No.
82-963 (June 27, 1983).  There, it is impossible to escape the
conclusion that the search warrant was defective, no matter what the
standard of review.  Yet, as explained in our opening brief (at 67-68
& n.31), the defect was strictly technical and amounted to no more
than harmless error.  In such cases, reviewing courts should be free
to consider the nature and effect of the error in determining whether
the exclusionary "remedy" is appropriately invoked.  (Respondents
Sanchez, et al. appear to concede this point in their brief (at 35 &
n.19).)

   /2/ Respondent Leon seems to argue (Br. 66) that the "cost of one
marijuana conviction" is a small price to pay for the benefit of the
decision in Prouse.  As we have shown above, however, even that cost
need not have been incurred.

   /3/ If respondents and their amici are correct in their assertion
that a reasonable mistake exception to the exclusionary rule would
"freeze" the development of Fourth Amendment law, then it logically
follows that the Court unwittingly "froze" the development of other
constitutional rights when in Harlow v. Fitzgerald, 457 U.S. 800
(1982), it approved a good-faith defense for Executive Branch
officials sued for damages that is essentially the same as what we
propose here.  We doubt that the Court thought it was doing any such
thing or, if it was, that the outcome of the case should have turned
on the effect the decision would have on opportunities for future
litigation.

   /4/ Respondents offer no explanation for the numerous cases noted
in our opening brief (at 85 n.51) in which courts decide the merits of
Fouth Amendment claims before deciding that the error, if any, was
harmless.  Yet respondents' position would require the conclusion that
all of those rulings were beyond the power of the courts to make.

   /5/ In the civil context, "'good faith' immunity is an affirmative
defense that must be pleaded by a defendant official." Harlow v.
Fitzgerald, 457 U.S. 800, 815 (1982);  Gomez v. Toledo, 446 U.S. 635
(1980).  If the same analytic framework were to apply in the context
of a reasonable mistake exception to the exclusionary rule, a court
surely would be free to consider the defendant's claim of a Fourth
Amendment violation before taking up the prosecution's assertion of an
affirmative defense.

   /6/ Even assuming arguendo some merit to respondents' position on
this issue, the most it would support would be a small exception to
the modification of the exclusionary rule that we propose.  Most of
the cases in which it would be appropriate to apply a reasonable
mistake exception will involve sui generis factual situations that
either are or are not compatible with existing law.  Whether or not
courts would retain the power to decide such cases is relatively
unimportant, because the decisions would be of little importance in
guiding future conduct in anything but precisely the same factual
situation.  Cases raising pure issues of Fourth Amendment law never
before addressed are relatively rare, however, and it is only those
cases to which respondents' argument has any relevance.

   /7/ Respondents fail to account for United States v. Janis, 428
U.S. 433 (1976), in which the Court sanctioned the use in a federal
civil tax proceeding of evidence obtained in violation of the Fourth
Amendment by local law enforcement officials.  The Court's analysis of
the case in terms of the amount of deterrence to be obtained versus
the costs of suppression would not be supportable under the "personal
right" doctrine because there was no question that Janis's "personal
rights" had been violated by the unlawful state search.

   /8/ Judge Wilkey has offered one explanation for this phenomenon
(Wilkey, supra, at 536-537):

      (T)he percentage of prosecutions lost because of the
      exclusionary rule * * * will remain about the same, no matter
      what the law is.  This is true because any intelligent
      prosecutor's office will immediately adjust itself to the most
      recent decision on the exclusionary rule or any other principle
      of law affecting the chance of conviction or acquittal in future
      cases.  No matter whether the latest case increases or decreases
      the likelihood of suppression of evidence, the prosecutor will
      adjust his decisions about which accused criminals to prosecute
      on the basis of the law which is now actually in effect.

         In other words, the prosecutor will always bring all of the
      cases which he is confident of winning, and a number of cases
      which are on the borderline * * *.  But * * * the prosecutor
      will change his assessment of the probably winnable and the
      improbably winnable as the shifting tides of jurisprudence from
      the higher courts inform him of where the law is.  Hence, the
      percentage of prosecutions won and lost will remain about the
      same in every intelligent, up-to-date prosecutor's office, no
      matter what the law is or how the rules change.

   Another explanation is that the world respondents depict appears to
be one in which very few Fourth Amendment violations occur or, if they
do, they are visited primarily upon innocent persons who never have
the opportunity to invoke the exclusionary rule.  In either event, if
the rule actually has as little practical effect as respondents
contend, it is difficult to grasp the justification for maintaining it
in cases such as the present one.

   /9/ Although respondents paint a picture of magistrates across the
nation issuing vast numbers of wholly unjustified warrants, they fail
to cite any substantial body of case law for their assumptions, and we
doubt that the cases would bear them out.  In any event, warrants so
totally lacking any basis for issuance would not fall within the scope
of a reasonable mistake exception to the exclusionary rule (see Gov't
Br. 65-66 & n.28).

   /10/ As Justice White noted in his concurrence in Gates (slip op.
18 n.17), this Court's holding in Shadwick v. City of Tampa, 407 U.S.
345 (1972), was quite narrow.  Although the Court upheld the issuance
by non-lawyers of arrest warrants for breaches of municipal
ordinances, it did not hold, in Shadwick or in any other case, that
any person taken off the street can issue any type of warrant.
Rather, "an issuing magistrate must * * * be neutral and detached, and
he must be capable of determining whether probable cause exists for
the requested arrest or search" (Shadwick, 407 U.S. at 350 (emphasis
added)).  Thus, the solution to problems of the type encountered in
State v. Upchurch, 267 N.C. 417, 148 S.E.2d 259 (1966) (see Leon Br.
11 & n.10), likes not in the exclusionary rule as applied on a
case-by-case basis, but rather in disqualification of "magistrates"
who do not meet Shadwick's dual requirements.  See Coolidge v. New
Hampshire, 403 U.S. 443 (1971).

   /11/ Respondents criticize us for failing to define the "reasonably
well-trained officer" with absolute precision (Leon Br. 33-34;
Sanchez, et al. Br. 46 n.34).  We continue to believe that a complete
definition can best be developed through initial consideration by
lower courts.  But that is not to say that the question is as murky as
respondents would have the Court believe.  For example, the reasonably
well-trained officer would be expected to know the governing law in
the jurisdiction in which a particular case is tried.  In this case,
therefore, Officer Rombach should be held to a standard of knowledge
that encompasses the relevant decisions of this Court and the Ninth
Circuit.  It would not matter whether the officer was an FBI agent, a
city police officer, or a rural deputy sheriff;  regardless of the
officer's particular background, he would have to meet the standards
of the court in which the evidence is sought to be admitted.

   /12/ See, e.g., FBI, U.S. Dep't of Justice, Legal Handbook for
Special Agents Secs. 2-6, 2-7.1, 2-7.2 (Aug. 27, 1982).  While the
practice among the states undoubtedly varies, it is our experience
that law enforcement officers generally consult with prosecutors prior
to applying for search warrants.  In this case, for example, Officer
Randolph consulted with three deputy district attorneys (Pet. App.
14a).

   /13/ Respondent Leon also bases his argument on California law (Br.
73 nn.140 & 141).  As previously noted (see pages 23-24 note 11,
supra), California law is irrelevant to what should be expected of a
reasonably well-trained police officer in a federal prosecution.

   /14/ Because the application of a reasonable mistake exception was
not adjudicated below, the most that can be made of respondent Leon's
argument is a remand for initial determination by the courts below.
We would have no objection to such a proceeding if the Court deems it
necessary.