Marvin ALLEN et al., Petitioners, v. Willie McCURRY.

At a hearing before his criminal trial in a Missouri court, the respondent, Willie McCurry, invoked the Fourth and Fourteenth Amendments to suppress evidence that had been seized by the police. The trial court denied the suppression motion in part, and McCurry was subsequently convicted after a jury trial. The conviction was later affirmed on appeal. State v. McCurry, 587 S.W.2d 337 (Mo.App.1979). Because he did not assert that the state courts had denied him a "full and fair opportunity" to litigate his search and seizure claim, McCurry was barred by this Court's decision in Stone v. Powell, 428 U.S. 465, 96 S.Ct. 3037, 49 L.Ed.2d 1067, from seeking a writ of habeas corpus in a federal district court. Nevertheless, he sought federal-court redress for the alleged constitutional violation by bringing a damages suit under 42 U.S.C. § 1983 against the officers who had entered his home and seized the evidence in question. We granted certiorari to consider whether the unavailability of federal habeas corpus prevented the police officers from raising the state courts' partial rejection of McCurry's constitutional claim as a collateral estoppel defense to the § 1983 suit against them for damages. 444 U.S. 1070, 100 S.Ct. 1012, 62 L.Ed.2d 751.

* In April 1977, several undercover police officers, following an informant's tip that McCurry was dealing in heroin, went to his house in St. Louis, Mo., to attempt a purchase.1 Two officers, petitioners Allen and Jacobsmeyer, knocked on the front door, while the other officers hid nearby. When McCurry opened the door, the two officers asked to buy some heroin "caps." McCurry went back into the house and returned soon thereafter, firing a pistol at and seriously wounding Allen and Jacobsmeyer. After a gun battle with the other officers and their reinforcements, McCurry retreated into the house; he emerged again when the police demanded that he surrender. Several officers then entered the house without a warrant, purportedly to search for other persons inside. One of the officers seized drugs and other contraband that lay in plain view, as well as additional contraband he found in dresser drawers and in auto tires on the porch.

McCurry was charged with possession of heroin and assault with intent to kill. At the pretrial suppression hearing, the trial judge excluded the evidence seized from the dresser drawers and tires, but denied suppression of the evidence found in plain view. McCurry was convicted of both the heroin and assault offenses.

McCurry subsequently filed the present § 1983 action for $1 million in damages against petitioners Allen and Jacobsmeyer, other unnamed individual police officers, and the city of St. Louis and its police department. The complaint alleged a conspiracy to violate McCurry's Fourth Amendment rights, an unconstitutional search and seizure of his house, and an assault on him by unknown police officers after he had been arrested and handcuffed. The petitioners moved for summary judgment. The District Court apparently under stood the gist of the complaint to be the allegedly unconstitutional search and seizure and granted summary judgment, holding that collateral estoppel prevented McCurry from relitigating the search-and-seizure question already decided against him in the state courts. 466 F.Supp. 514 (ED Mo.1978).2

The Court of Appeals reversed the judgment and remanded the case for trial. 606 F.2d 795 (CA8 1979).3 The appellate court said it was not holding that collateral estoppel was generally inapplicable in a § 1983 suit raising issues determined against the federal plaintiff in a state criminal trial. Id. at 798. But noting that Stone v. Powell, supra, barred McCurry from federal habeas corpus relief, and invoking "the special role of the federal courts in protecting civil rights," 606 F.2d, at 799, the court concluded that the § 1983 suit was McCurry's only route to a federal forum for his constitutional claim and directed the trial court to allow him to proceed to trial unencumbered by collateral estoppel.4

The federal courts have traditionally adhered to the related doctrines of res judicata and collateral estoppel. Under res judicata, a final judgment on the merits of an action precludes the parties or their privies from relitigating issues that were or could have been raised in that action. Cromwell v. County of Sac, 94 U.S. 351, 352, 24 L.Ed. 195. Under collateral estoppel, once a court has decided an issue of fact or law necessary to its judgment, that decision may preclude relitigation of the issue in a suit on a different cause of action involving a party to the first case. Montana v. United States, 440 U.S. 147, 153, 99 S.Ct. 970, 973, 59 L.Ed.2d 210.5 As this Court and other courts have often recognized, res judicata and collateral estoppel relieve parties of the cost and vexation of multiple lawsuits, conserve judicial resources, and, by preventing inconsistent decisions, encourage reliance on adjudication. Id., at 153-154, 99 S.Ct., at 973-974.

In recent years, this Court has reaffirmed the benefits of collateral estoppel in particular, finding the policies underlying it to apply in contexts not formerly recognized at common law. Thus, the Court has eliminated the requirement of mutuality in applying collateral estoppel to bar relitigation of issues decided earlier in federal-court suits, Blonder-Tongue Laboratories, Inc. v. University of Illinois Foundation, 402 U.S. 313, 91 S.Ct. 1434, 28 L.Ed.2d 788, and has allowed a litigant who was not a party to a federal case to use collateral estoppel "offensively" in a new federal suit against the party who lost on the decided issue in the first case, Parklane Hosiery Co. v. Shore, 439 U.S. 322, 99 S.Ct. 645, 58 L.Ed.2d 552.6 But one general limitation the Court has repeatedly recognized is that the concept of collateral estoppel cannot apply when the party against whom the earlier decision is asserted did not have a "full and fair opportunity" to litigate that issue in the earlier case. Montana v. United States, supra, at 153, 99 S.Ct., at 973; Blonder-Tongue Laboratories, Inc. v. University of Illinois Foundation, supra, 402 U.S., at 328-329, 91 S.Ct., at 1443.7

The federal courts generally have also consistently accorded preclusive effect to issues decided by state courts. E. g., Montana v. United States, supra; Angel v. Bullington, 330 U.S. 183, 67 S.Ct. 657, 91 L.Ed. 832. Thus, res judicata and collateral estoppel not only reduce unnecessary litigation and foster reliance on adjudication, but also promote the comity between state and federal courts that has been recognized as a bulwark of the federal system. See Younger v. Harris, 401 U.S. 37, 43-45, 91 S.Ct. 746, 750-51, 27 L.Ed.2d 669.

Indeed, though the federal courts may look to the common law or to the policies supporting res judicata and collateral estoppel in assessing the preclusive effect of decisions of other federal courts, Congress has specifically required all federal courts to give preclusive effect to state-court judgments whenever the courts of the State from which the judgments emerged would do so:

"[J]udicial proceedings [of any court of any State] shall have the same full faith and credit in every court within the United States and its Territories and Possessions as they have by law or usage in the courts of such State. . . ." 28 U.S.C. § 1738 (1976).8

Huron Holding Corp. v. Lincoln Mine Operating Co., 312 U.S. 183, 193, 61 S.Ct. 513, 517, 85 L.Ed. 725; Davis v. Davis, 305 U.S. 32, 40, 59 S.Ct. 3, 6, 85 L.Ed. 26. It is against this background that we examine the relationship of § 1983 and collateral estoppel, and the decision of the Court of Appeals in this case.

This Court has never directly decided whether the rules of res judicata and collateral estoppel are generally applicable to § 1983 actions. But in Preiser v. Rodriguez, 411 U.S. 475, 497, 93 S.Ct. 1827, 1840, 36 L.Ed.2d 439, the Court noted with implicit approval the view of other federal courts that res judicata principles fully apply to civil rights suits brought under that statute. See also Huffman v. Pursue, Ltd., 420 U.S. 592, 606, n. 18, 95 S.Ct. 1200, 1209, n. 18, 43 L.Ed.2d 482; Wolff v. McDonnell, 418 U.S. 539, 554, n. 12, 94 S.Ct. 2963, 2974, n. 12, 41 L.Ed.2d 935.9 And the virtually unanimous view of the Courts of Appeals since Preiser has been that § 1983 presents no categorical bar to the application of res judicata and collateral estoppel concepts.10 These federal appellate court decisions have spoken with little explanation or citation in assuming the compatibility of § 1983 and rules of preclusion, but the statute and its legislative history clearly support the courts' decisions.

Because the requirement of mutuality of estoppel was still alive in the federal courts until well into this century, see Blonder-Tongue Laboratories, Inc. v. University of Illinois Foundation, supra, at 322-323, 91 S.Ct., at 1439-1440, the drafters of the 1871 Civil Rights Act, of which § 1983 is a part, may have had less reason to concern themselves with rules of preclusion than a modern Congress would. Nevertheless, in 1871 res judicata and collateral estoppel could certainly have applied in federal suits following state-court litigation between the same parties or their privies, and nothing in the language of § 1983 remotely expresses any congressional intent to contravene the common-law rules of preclusion or to repeal the express statutory requirements of the predecessor of 28 U.S.C. § 1738, see n. 8, supra. Section 1983 creates a new federal cause of action.11 It says nothing about the preclusive effect of state-court judgments.12

Moreover, the legislative history of § 1983 does not in any clear way suggest that Congress intended to repeal or restrict the traditional doctrines of preclusion. The main goal of the Act was to override the corrupting influence of the Ku Klux Klan and its sympathizers on the governments and law enforcement agencies of the Southern States, see Monroe v. Pape, 365 U.S. 167, 174, 81 S.Ct. 473, 477, 5 L.Ed.2d 492, and of course the debates show that one strong motive behind its enactment was grave congressional concern that the state courts had been deficient in protecting federal rights, Mitchum v. Foster, 407 U.S. 225, 241-242, 92 S.Ct. 2151, 2161-2162, 32 L.Ed.2d 705; Monroe v. Pape, supra, at 180, 81 S.Ct., at 480.13 But in the context of the legislative history as a whole, this congressional concern lends only the most equivocal support to any argument that, in cases where the state courts have recognized the constitutional claims asserted and provided fair procedures for determining them, Congress intended to override § 1738 or the common-law rules of collateral estoppel and res judicata. Since repeals by implication are disfavored, Radzanower v. Touche Ross & Co., 426 U.S. 148, 154, 96 S.Ct. 1989, 1993, 48 L.Ed.2d 540, much clearer support than this would be required to hold that § 1738 and the traditional rules of preclusion are not applicable to § 1983 suits.

As the Court has understood the history of the legislation, Congress realized that in enacting § 1983 it was altering the balance of judicial power between the state and federal courts. See Mitchum v. Foster, supra, at 241, 92 S.Ct., at 2161. But in doing so, Congress was adding to the jurisdiction of the federal courts, not subtracting from that of the state courts. See Monroe v. Pape, supra, at 183, 81 S.Ct., at 481 ("The federal remedy is supplementary to the state remedy . . .").14 The debates contain several references to the concurrent jurisdiction of the state courts over federal questions,15 and numerous suggestions that the state courts would retain their established jurisdiction so that they could, when the then current political passions abated, demonstrate a new sensitivity to federal rights.16

To the extent that it did intend to change the balance of power over federal questions between the state and federal courts, the 42d Congress was acting in a way thoroughly consistent with the doctrines of preclusion. In reviewing the legislative history of § 1983 in Monroe v. Pape, supra, the Court inferred that Congress had intended a federal remedy in three circumstances: where state substantive law was facially unconstitutional, where state procedural law was inadequate to allow full litigation of a constitutional claim, and where state procedural law, though adequate in theory, was inadequate in practice. 365 U.S., at 173-174, 81 S.Ct., at 476-477. In short, the federal courts could step in where the state courts were unable or unwilling to protect federal rights. Id., at 176, 81 S.Ct., at 478. This understanding of § 1983 might well support an exception to res judicata and collateral estoppel where state law did not provide fair procedures for the litigation of constitutional claims, or where a state court failed to even acknowledge the existence of the constitutional principle on which a litigant based his claim. Such an exception, however, would be essentially the same as the important general limit on rules of preclusion that already exists: Collateral estoppel does not apply where the party against whom an earlier court decision is asserted did not have a full and fair opportunity to litigate the claim or issue decided by the first court. See supra, at 95. But the Court's view of § 1983 in Monroe lends no strength to any argument that Congress intended to allow relitigation of federal issues decided after a full and fair hearing in a state court simply because the state court's decision may have been erroneous.17

The Court of Appeals in this case acknowledged that every Court of Appeals that has squarely decided the question has held that collateral estoppel applies when § 1983 plaintiffs attempt to relitigate in federal court issues decided against them in state criminal proceedings.18 But the court noted that the only two federal appellate decisions invoking collateral estoppel to bar relitigation of Fourth Amendment claims decided adversely to the § 1983 plaintiffs in state courts came before this Court's decision inStone v. Powell, 428 U.S. 465, 96 S.Ct. 3037, 49 L.Ed.2d 1067.19 It also noted that some of the decisions holding collateral estoppel applicable to § 1983 actions were based at least in part on the estopped party's access to another federal forum through habeas corpus.20 The Court of Appeals thus concluded that since Stone v. Powell had removed McCurry's right to a hearing of his Fourth Amendment claim in federal habeas corpus, collateral estoppel should not deprive him of a federal judicial hearing of that claim in a § 1983 suit.

Stone v. Powell does not provide a logical doctrinal source for the court's ruling. This Court in Stone assessed the costs and benefits of the judge-made exclusionary rule within the boundaries of the federal courts' statutory power to issue writs of habeas corpus, and decided that the incremental deterrent effect that the issuance of the writ in Fourth Amendment cases might have on police conduct did not justify the cost the writ imposed upon the fair administration of criminal justice. 428 U.S., at 489-496, 96 S.Ct., at 3050-3053. The Stone decision concerns only the prudent exercise of federal-court jurisdiction under 28 U.S.C. § 2254. It has no bearing on § 1983 suits or on the question of the preclusive effect of state-court judgments.

The actual basis of the Court of Appeals' holding appears to be a generally framed principle that every person asserting a federal right is entitled to one unencumbered opportunity to litigate that right in a federal district court, regardless of the legal posture in which the federal claim arises. But the authority for this principle is difficult to discern. It cannot lie in the Constitution, which makes no such guarantee, but leaves the scope of the jurisdiction of the federal district courts to the wisdom of Congress.21 And no such authority is to be found in § 1983 itself. For reasons already discussed at length, nothing in the language or legislative history of § 1983 proves any congressional intent to deny binding effect to a state-court judgment or decision when the state court, acting within its proper jurisdiction, has given the parties a full and fair opportunity to litigate federal claims, and thereby has shown itself willing and able to protect federal rights. And nothing in the legislative history of § 1983 reveals any purpose to afford less deference to judgments in state criminal proceedings than to those in state civil proceedings.22 There is, in short, no reason to believe that Congress intended to provide a person claiming a federal right an unrestricted opportunity to relitigate an issue already decided in state court simply because the issue arose in a state proceeding in which he would rather not have been engaged at all.23

Through § 1983, the 42d Congress intended to afford an opportunity for legal and equitable relief in a federal court for certain types of injuries. It is difficult to believe that the drafters of that Act considered it a substitute for a federal writ of habeas corpus, the purpose of which is not to redress civil injury, but to release the applicant from unlawful physical confinement, Preiser v. Rodriguez, 411 U.S., at 484, 93 S.Ct., at 1833; Fay v. Noia, 372 U.S. 391, 399, n. 5, 83 S.Ct. 822, 827, n. 5, 9 L.Ed.2d 837,24 particularly in light of the extremely narrow scope of federal habeas relief for state prisoners in 1871.

The only other conceivable basis for finding a universal right to litigate a federal claim in a federal district court is hardly a legal basis at all, but rather a general distrust of the capacity of the state courts to render correct decisions on constitutional issues. It is ironic that Stone v. Powell provided the occasion for the expression of such an attitude in the present litigation, in view of this Court's emphatic reaffirmation in that case of the constitutional obligation of the state courts to uphold federal law, and its expression of confidence in their ability to do so. 428 U.S., at 493-494, n. 35, 96 S.Ct., at 3051-52, n. 35; see Robb v. Connolly, 111 U.S. 624, 637, 4 S.Ct. 544, 551, 28 L.Ed. 542 (Harlan, J.).

The Court of Appeals erred in holding that McCurry's inability to obtain federal habeas corpus relief upon his Fourth Amendment claim renders the doctrine of collateral estoppel inapplicable to his § 1983 suit.25 Accordingly, the judgment is reversed, and the case is remanded to the Court of Appeals for proceedings consistent with this opinion.

It is so ordered.

Justice BLACKMUN, with whom Justice BRENNAN and Justice MARSHALL join, dissenting.

The legal principles with which the Court is concerned in this civil case obviously far transcend the ugly facts of respondent's criminal convictions in the courts of Missouri for heroin possession and assault.

The Court today holds that notions of collateral estoppel apply with full force to this suit brought under 42 U.S.C. § 1983. In my view, the Court, in so ruling, ignores the clear import of the legislative history of that statute and disregards the important federal policies that underlie its enforcement. It also shows itself insensitive both to the significant differences between the § 1983 remedy and the exclusionary rule, and to the pressures upon a criminal defendant that make a free choice of forum illusory. I do not doubt that principles of preclusion are to be given such effect as is appropriate in a § 1983 action. In many cases, the denial of res judicata or collateral estoppel effect would serve no purpose and would harm relations between federal and state tribunals. Nonetheless, the Court's analysis in this particular case is unacceptable to me. It works injustice on this § 1983 plaintiff, and it makes more difficult the consistent protection of constitutional rights, a consideration that was at the core of the enacters' intent. Accordingly, I dissent.

In deciding whether a common-law doctrine is to apply to § 1983 when the statute itself is silent, prior cases uniformly have accorded the intent of the legislators great weight.1 For example, in reference to the judicially created immunity doctrine, the Court has observed that when the "immunity claimed . . . was well established at common law at the time § 1983 was enacted, and where its rationale was compatible with the purposes of the Civil Rights Act, we have construed the statute to incorporate that immunity." Owen v. City of Independence, 445 U.S. 622, 638, 100 S.Ct. 1398, 1409, 63 L.Ed.2d 673 (1980).2 This very proper inquiry must be made in order to ensure that § 1983 will continue to serve the important goals intended for it by the 42d Congress. In the present case, however, the Court minimizes the significance of the legislative history and discounts its own prior explicit interpretations of the statute. Its discussion is limited to articulating what it terms the single fundamental principle of res judicata and collateral estoppel.

Respondent's position merits a quite different analysis. Although the legislators of the 42d Congress did not expressly state whether the then existing common-law doctrine of preclusion would survive enactment of § 1983, they plainly anticipated more than the creation of a federal statutory remedy to be administered indifferently by either a state or a federal court.3 The legislative intent, as expressed by supporters4 and understood by opponents,5 was to restructure relations between the state and federal courts.6 Congress deliberately opened the federal courts to individual citizens in response to the States' failure to provide justice in their own courts. Contrary to the view presently expressed by the Court, the 42d Congress was not concerned solely with procedural regularity. Even where there was procedural regularity, which the Court today so stresses, Congress believed that substantive justice was unobtainable.7 The availability of the federal forum was not meant to turn on whether, in an individual case, the state procedures were adequate. Assessing the state of affairs as a whole, Congress specifically made a determination that federal oversight of constitutional determinations through the federal courts was necessary to ensure the effective enforcement of constitutional rights.

That the new federal jurisdiction was conceived of as concurrent with state jurisdiction does not alter the significance of Congress' opening the federal courts to these claims. Congress consciously acted in the broadest possible manner.8 The legislators perceived that justice was not being done in the States then dominated by the Klan, and it seems senseless to suppose that they would have intended the federal courts to give full preclusive effect to prior state adjudications. That supposition would contradict their obvious aim to right the wrongs perpetuated in those same courts.

I appreciate that the legislative history is capable of alternative interpretations. See the Court's opinion, ante, at 98-101. I would have thought, however, that our prior decisions made very clear which reading is required. The Court repeatedly has recognized that § 1983 embodies a strong congressional policy in favor of federal courts' acting as the primary and final arbiters of constitutional rights.9 In Monroe v. Pape, 365 U.S. 167, 81 S.Ct. 473, 51 L.Ed.2d 492 (1961), the Court held that Congress passed the legislation in order to substitute a federal forum for the ineffective, although plainly available, state remedies:

"It is abundantly clear that one reason the legislation was passed was to afford a federal right in federal courts because, by reason of prejudice, passion, neglect, intolerance or otherwise, state laws might not be enforced and the claims of citizens to the enjoyment of rights, privileges, and immunities guaranteed by the Fourteenth Amendment might be denied by the state agencies." Id., at 180, 81 S.Ct., at 480.10

The Court appears to me to misconstrue the plain meaning of Monroe. It states that in that case, "the Court inferred that Congress had intended a federal remedy in three circumstances: where state substantive law was facially unconstitutional, where state procedural law was inadequate to allow full litigation of a constitutional claim, and where state procedural law, though adequate in theory, was inadequate in practice." Ante, at 100-101. It is true that the Court in Monroe described those three circumstances as the "three main aims" of the legislation. 365 U.S., at 173, 81 S.Ct., at 476. Yet in that case, the Court's recounting of the legislative history and its articulation of these three purposes were intended only as illustrative of why the 42d Congress chose to establish a federal remedy in federal court, not as a delineation of when the remedy would be available. The Court's conclusion was that this remedy was to be available no matter what the circumstances of state law:

"It is no answer that the State has a law which if enforced would give relief. The federal remedy is supplementary to the state remedy, and the latter need not be first sought and refused before the federal one is invoked. Hence the fact that Illinois by its constitution and laws outlaws unreasonable searches and seizures is no barrier to the present suit in the federal court." Id., at 183, 81 S.Ct., at 481.

In Mitchum v. Foster, 407 U.S. 225, 92 S.Ct. 2151, 32 L.Ed.2d 705 (1972), the Court reiterated its understanding of the effect of § 1983 upon state and federal relations:

"Section 1983 was thus a product of a vast transformation from the concepts of federalism that had prevailed in the late 18th century. . . . The very purpose of § 1983 was to interpose the federal courts between the States and the people, as guardians of the people's federal rights-to protect the people from unconstitutional action under color of state law, 'whether that action be executive, legislative, or judicial.' Ex parte Virginia, 100 U.S. [339], at 346 [25 L.Ed. 676]." Id., at 242, 92 S.Ct., at 2162.11

At the very least, it is inconsistent now to narrow, if not repudiate, the meaning of Monroe and Mitchum and to alter our prior understanding of the distribution of power between the state and federal courts.

One should note also that in England v. Medical Examiners, 375 U.S. 411, 84 S.Ct. 461, 11 L.Ed.2d 440 (1964), the Court had affirmed the federal courts' special role in protecting constitutional rights under § 1983. In that case it held that a plaintiff required by the abstention doctrine to submit his constitutional claim first to a state court could not be precluded entirely from having the federal court, in which he initially had sought relief, pass on his constitutional claim. The Court relied on "the unqualified terms in which Congress, pursuant to constitutional authorization, has conferred specific categories of jurisdiction upon the federal courts," and on its "fundamental objections to any conclusion that a litigant who has properly invoked the jurisdiction of a Federal District Court to consider federal constitutional claims can be compelled, without his consent and through no fault of his own, to accept instead a state court's determination of those claims." Id., at 415, 84 S.Ct., at 464. The Court set out its understanding as to when a litigant in a § 1983 case might be precluded by prior litigation, holding that "if a party freely and without reservation submits his federal claims for decision by the state courts, litigates them there, and has them decided there, then-whether or not he seeks direct review of the state decision in this Court-he has elected to forgo his right to return to the District Court." Id., at 419, 84 S.Ct., at 466. I do not understand why the Court today should abandon this approach.

The Court now fashions a new doctrine of preclusion, applicable only to actions brought under § 1983, that is more strict and more confining than the federal rules of preclusion applied in other cases. In Montana v. United States, 440 U.S. 147, 99 S.Ct. 970, 59 L.Ed.2d 210 (1979), the Court pronounced three major factors to be considered in determining whether collateral estoppel serves as a barrier in the federal court:

"[W]hether the issues presented . . . are in substance the same . . .; whether controlling facts or legal principles have changed significantly since the state-court judgment; and finally, whether other special circumstances warrant an exception to the normal rules of preclusion." Id., at 155, 99 S.Ct., at 975.

But now the Court states that the collateral-estoppel effect of prior state adjudication should turn on only one factor, namely, what it considers the "one general limitation" inherent in the doctrine of preclusion: "that the concept of collateral estoppel cannot apply when the party against whom the earlier decision is asserted did not have a 'full and fair opportunity' to litigate that issue in the earlier case." Ante, at 95, 101. If that one factor is present, the Court asserts, the litigant properly should be barred from relitigating the issue in federal court.12 One cannot deny that this factor is an important one. I do not believe, however, that the doctrine of preclusion requires the inquiry to be so narrow,13 and my understanding of the policies underlying § 1983 would lead me to consider all relevant factors in each case before concluding that preclusion was warranted.

In this case, the police officers seek to prevent a criminal defendant from relitigating the constitutionality of their conduct in searching his house, after the state trial court had found that conduct in part violative of the defendant's Fourth Amendment rights and in part justified by the circumstances. I doubt that the police officers, now defendants in this § 1983 action, can be considered to have been in privity with the State in its role as prosecutor. Therefore, only "issue preclusion"14 is at stake.

The following factors persuade me to conclude that this respondent should not be precluded from asserting his claim in federal court. First, at the time § 1983 was passed, a nonparty's ability, as a practical matter, to invoke collateral estoppel was nonexistent. One could not preclude an opponent from relitigating an issue in a new cause of action, though that issue had been determined conclusively in a prior proceeding, unless there was "mutuality."15 Additionally, the definitions of "cause of action" and "issue" were narrow.16 As a result, and obviously, no preclusive effect could arise out of a criminal proceeding that would affect subsequent civil litigation. Thus, the 42d Congress could not have anticipated or approved that a criminal defendant, tried and convicted in state court, would be precluded from raising against police officers a constitutional claim arising out of his arrest.

Also, the process of deciding in a state criminal trial whether to exclude or admit evidence is not at all the equivalent of a § 1983 proceeding. The remedy sought in the latter is utterly different. In bringing the civil suit the criminal defendant does not seek to challenge his conviction collaterally. At most, he wins damages. In contrast, the exclusion of evidence may prevent a criminal conviction. A trial court, faced with the decision whether to exclude relevant evidence, confronts institutional pressures that may cause it to give a different shape to the Fourth Amendment right from what would result in civil litigation of a damages claim. Also, the issue whether to exclude evidence is subsidiary to the purpose of a criminal trial, which is to determine the guilt or innocence of the defendant, and a trial court, at least subconsciously, must weigh the potential damage to the truth-seeking process caused by excluding relevant evidence. See Stone v. Powell, 428 U.S. 465, 489-495, 96 S.Ct. 3037, 3050-3052, 49 L.Ed.2d 1067 (1976). Cf. Bivens v. Six Unknown Federal Narcotics Agents, 403 U.S. 388, 411-424, 91 S.Ct. 1999, 2012-2018, 29 L.Ed.2d 619 (1971) (dissenting opinion).

A state criminal defendant cannot be held to have chosen "voluntarily" to litigate his Fourth Amendment claim in the state court. The risk of conviction puts pressure upon him to raise all possible defenses.17 He also faces uncertainty about the wisdom of forgoing litigation on any issue, for there is the possibility that he will be held to have waived his right to appeal on that issue. The "deliberate bypass" of state procedures, which the imposition of collateral estoppel under these circumstances encourages, surely is not a preferred goal. To hold that a criminal defendant who raises a Fourth Amendment claim at his criminal trial "freely and without reservation submits his federal claims for decision by the state courts," see England v. Medical Examiners, 375 U.S., at 419, 84 S.Ct., at 466, is to deny reality. The criminal defendant is an involuntary litigant in the state tribunal, and against him all the forces of the State are arrayed. To force him to a choice between forgoing either a potential defense or a federal forum for hearing his constitutional civil claim is fundamentally unfair.

I would affirm the judgment of the Court of Appeals.