US SUPREME COURT DECISIONS

Based upon the affidavit of a police officer, a Los Angeles judge issued a search warrant, pursuant to which the police seized from respondent $4,940 in cash and certain wagering records. The officer advised the Internal Revenue Service (IRS) that respondent had been arrested for bookmaking activity. Using a calculation based upon the seized evidence, the IRS assessed respondent for wagering excise taxes and levied upon the $4,940 in partial satisfaction. In the subsequent state criminal proceeding against respondent, the trial court found the police officer's affidavit defective, granted a motion to quash the warrant, and ordered the seized items returned to the respondent, except for the $4,940. Respondent filed a refund claim for the $4,940 and, later, this action. The Government answered and counterclaimed for the unpaid balance of the assessment. Respondent moved to suppress the evidence seized and all copies thereof, and to quash the assessment. The District Court, after a hearing, concluded that respondent was entitled to a refund, because the assessment "was based in substantial part, if not completely, on illegally procured evidence in violation of [respondent's] Fourth Amendment rights," and that, under the circumstances, respondent was not required to prove the extent of the claimed refund. The assessment was quashed and the counterclaim accordingly was dismissed. The Court of Appeals affirmed.

Held: The judicially created exclusionary rule should not be extended to forbid the use in the civil proceeding of one sovereign (here the Federal Government) of evidence illegally seized by a criminal law enforcement agent of another sovereign (here the state government), since the likelihood of deterring law enforcement conduct through such a rule is not sufficient to outweigh the societal costs imposed by the exclusion. Pp. 428 U. S. 443-460.

(a) The prime, if not the sole, purpose of the exclusionary rule "is to deter future unlawful police conduct." Pp. 428 U. S. 443-447.

(b) Whether the exclusionary rule is a deterrent has not yet been demonstrated. Assuming, however, that it is a deterrent, chanrobles.com-red

Page 428 U. S. 434

then its use in situations where it is now applied must be deemed to suffice to accomplish its purpose, because the local law enforcement official is already "punished" by the exclusion of the evidence in both the state and the federal criminal trials. The additional marginal deterrence provided by its extension in cases like this one does not outweigh the societal costs of excluding concededly relevant evidence. Pp. 447-460.

Reversed and remanded.

BLACKMUN, J., delivered the opinion of the Court, in which BURGER, C.J.,and WHITE, POWELL, and REHNQUIST, JJ., joined. BRENNAN, J., filed a dissenting opinion, in which MARSHALL, J., joined, post, p. 428 U. S. 460. STEWART, J., filed a dissenting opinion, post, p. 428 U. S. 460. STEVENS, J., took no part in the consideration or decision of the case.