dissenting.
The Court today holds that another trial of respondent, following a mistrial declared over his vehement objection, is not prohibited by the Double Jeopardy Clause. To reach this result, my Brethren accord a substantial degree of deference to a trial court finding that the Court simply assumes was made but that appears nowhere in the record. Because of the silence of the record on the crucial question whether there was “manifest necessity” for a mistrial, I believe that another trial of respondent would violate his constitutional right not to be twice put in jeopardy for the same offense. I therefore dissent.
My disagreement with the majority is a narrow one. I fully concur in its view that the constitutional protection of the Double Jeopardy Clause “embraces the defendant’s Valued right to have his trial completed by a particular tribunal,’ ” since a second prosecution inevitably “increases the financial and emotional burden on the accused, prolongs the period in which he is stigmatized by an unresolved accusation of wrongdoing, and may even enhance the risk that an innocent defendant may be convicted.” Ante, at 503-504 (footnotes omitted). For these reasons, I also agree that, where a mistrial is declared over a defendant’s objections, a new trial is permissible only if the termination of the earlier trial was justified by a “manifest necessity” and that the prosecution must shoulder the “heavy” burden of demonstrating such a “high degree” of necessity. Ante, at 505-506. Nor do I quarrel with the proposition that reviewing courts must accord substantial deference to a trial judge’s determination that the prejudicial impact of an improper opening statement is so *520great as to leave no- alternative but a mistrial to secure the ends of public justice. Ante, at 510, 513-514.1
Where I part ways from the Court is in its assumption that an “assessment of the prejudicial impact of improper argument,” ante, at 514, sufficient to support the need for a mistrial, may be implied from this record. As the courts below found,2 it is not apparent on the face of the record that termination of the trial was justified by a “manifest necessity” or was the only means by which the “ends of public justice” could be fulfilled, United States v. Perez, 9 Wheat. 579, 580 (1824). *521See also ante, at 511. Defense counsel’s improper remarks occupied only one page of a lengthy opening statement. Despite the fact that the prosecutor had vigorously interrupted the opening statement at numerous ipoints to assert various objections,3 he made no objection to the remarks that formed the basis for the mistrial. If the argument of defense counsel had had a visibly obvious impact on the jurors when uttered, it is hard to believe that this prosecutor would have waited until after the opening statement was finished and the luncheon recess concluded before making his objection known.
Although from this distance and in the absence of express findings it is impossible to determine the precise extent to which defense counsel’s remarks may have prejudiced the jury against the State, the circumstances set forth above suggest that any such prejudice may have been minimal and subject to cure through less drastic alternatives.4 For example, the jury could have been instructed to disregard any mention of prior legal rulings as irrelevant to the issues at hand, and to consider as evidence only the testimony and exhibits admitted through witnesses on the stand.5 Were there doubt *522whether such instructions alone would suffice to cure the taint, the jury could have been questioned about the extent of any prejudice. Given the anticipated length of the trial (almost two weeks),6 it is not unlikely that, had the jury been appropriately instructed when the court first found defense counsel to have erred in his opening statement, any prejudice would have dissipated before deliberations were to begin. For these reasons, it is impossible to conclude that a finding of necessity was implicit in the mere grant of the mistrial.7
*523As the majority concedes, ante, at 501, there was no express determination or evaluation by the trial court of the degree of prejudice caused by the improper remarks; nor was there any exploration of possible alternatives to the drastic solution of declaring a mistrial; nor, indeed, any express indication on the face of the record that the trial court was aware of the dictates of the Perez doctrine. Over the two days during which the mistrial motion was argued, the entire thrust of the trial court’s questions and comments was to determine whether there was any legal basis for admitting into evidence the Arizona Supreme Court’s ruling that the prosecution in an earlier trial had suppressed evidence exculpatory of respondent, to which ruling defense counsel had adverted in opening statement.8 The tenor of the court’s remarks throughout— including its statement in declaring the mistrial9 — suggests that the only question considered was that of admissibility.10
*524There is no doubt that the trial court’s exploration of the evidentiary question was conscientious and deliberate. The majority infers from this care that the trial court must have been aware of the correct legal standard governing the permissibility of retrials following mistrials, and must impliedly, though not expressly, have made the requisite findings of necessity. The deliberation with which the trial court dealt with the evidentiary issue, however, only highlights its failure to address what I believe must be the key inquiry: whether a mistrial, and its abrogation of a defendant’s constitutionally protected interest in completing his trial before a particular tribunal, United States v. Jorn, 400 U. S. 470, 486 (1971) (plurality opinion of Harlan, J.); Wade v. Hunter, 336 U. S. 684, 689 (1949), is the only way to secure the public interest in a just disposition of the charges.
I do not propose that the Constitution invariably requires a trial judge to make findings of necessity on the record to justify the declaration of a mistrial over a defendant’s objec*525tions. For example, where the nature of the error is one that “would make reversal [of any conviction] on appeal a certainty,” Illinois v. Somerville, 410 U. S. 458, 464 (1973), the appropriate finding may be implied from the declaration of a mistrial.11 What the “manifest necessity” doctrine does require, in my view, is that the record make clear either that there were no meaningful and practical alternatives to a mistrial, or that the trial court scrupulously considered available alternatives and found all wanting but a termination of the proceedings. See United States v. Jorn, supra, at 485; Illinois v. Somerville, supra, at 478-479 (Marshall, J., dissenting). The record here, as demonstrated above, does neither.
Where the need for a mistrial is not “plain and obvious,” United States v. Perez, 9 Wheat., at 580, the importance of an affirmative indication that the trial court made the relevant findings is apparent. In the chaos of conducting a trial, with the welter of administrative as well as legal concerns that must occupy the mind of the trial judge, it is all too easy to overlook a legal rule or relevant factor in rendering decision. A requirement of some statement on the record addressed to the need for a mistrial would ensure that appropriate consideration is given to the efficacy of other alternatives and that mistrial decisions are not based upon improper, or only partly adequate, criteria. Of particular relevance here, moreover, it would facilitate proper appellate and habeas review, avoiding the need to speculate on the basis for the decision to terminate the trial.12 These considerations have special force when a *526mistrial is sought on the ground of jury bias resulting from trial counsel’s error. The trial court is uniquely situated to evaluate the seriousness of any such prejudice, see ante, at 513-514, and its failure contemporaneously to do so may preclude meaningful subsequent determination of whether the mistrial was properly granted over the defendant’s objection. Thus, where the necessity for a mistrial is not manifest on the face of the record, I would hold that the record must clearly indicate that the trial court made a considered choice among the available alternatives.13
Had the court here explored alternatives on the record, or made a finding of substantial and incurable prejudice or other “manifest necessity,” this would be a different case and one in which I would agree with both the majority’s reasoning and its result.14 On this ambiguous record, however, the *527absence of any such finding — and indeed of any express indication that the trial court applied the manifest-necessity doctrine — leaves open the substantial possibility that there was in fact no need to terminate the proceedings. While the Court states that a “high degree” of necessity is required before a mistrial may properly be granted, its reading of the record here is inconsistent with this principle.
I would therefore affirm the judgment of the Court of Appeals.
This proposition is essentially unremarkable. It is a truism that findings of fact by the trial court may not be set aside on appeal unless “clearly erroneous,” and that on review appropriate deference must be given to the trial court’s opportunity to judge the credibility of the witnesses. See, e. g., Fed. Rule Civ. Proc. 52 (a); Zenith Radio Corp. v. Hazeltine Research, Inc., 395 U. S. 100, 123 (1969). While the determination that there is no alternative but a mistrial to cure prejudice created by an improper opening statement is in part one of law, in a case of this sort it is based primarily on a factual evaluation of the extent to which the particular jury has been prejudiced.
Contrary to the majority’s implication, ante, at 502 nn. 8-9, the courts below did not hold that the absence of express findings relating to the necessity for a mistrial was by itself dispositive. Rather, the rulings of the District Court and the Court of Appeals were based on their respective conclusions that on this record it could not independently be determined that “the jury was prevented from arriving at a fair and impartial verdict,” and therefore that a finding of manifest necessity was not implicit in this record. 546 F. 2d 832; see App. 128-129 (District Court’s view that any prejudice could have been cured by cautionary instruction).
Nor can I agree with the majority that the Court of Appeals applied an inappropriate standard of review. It expressly recognized that “[t]he power to discharge a jury ... is discretionary with the trial court” and that, “[i]n the absence of clear abuse, we . . . normally . . . uphold discretionary orders of this nature.” 546 F. 2d, at 832. But this is so, noted the court, where “[i]n the usual case, the trial judge has observed the complained-of event, heard counsel, and made specific findings. Under such circumstances, a mistrial declaration accompanied by a finding that the jury could no longer render an impartial verdict would not lightly be set aside.” Ibid.
See App. 173, 176, 178, 182, 183.
As is recognized by the majority in its search for an implied finding that the prejudice was sufficient to warrant a mistrial, mere error by either the prosecutor or the defense is insufficient by itself to provide the “high degree” of necessity, ante, at 506, required to permit a retrial following the grant of a mistrial over the defendant’s objections. See United States v. Dinitz, 424 U. S. 600, 608 (1976), quoting United States v. Jorn, 400 U. S. 470, 484 (1971) (plurality opinion of Harlan, J.).
1 do not mean to suggest that curative instructions are always or even generally sufficient to cure prejudice resulting from evidentiary errors, see Bruton v. United States, 391 U. S. 123, 129 (1968), quoting Krulewitch v. United States, 336 U. S. 440, 453 (1949) (Jackson, J., concurring), particularly where the error is one by the prosecutor and must be shown to have been harmless beyond any reasonable doubt in order for the conviction to be sustained, see Chapman v. California, 386 U. S. 18, 21-24 (1967). However, it must be recognized that the cases are legion in which convictions have been upheld despite the jury’s exposure to improper material *522relating to the defendant’s past conduct, often because curative instructions have been found sufficient to dispel any prejudice. See, e. g., United States v. Bloom, 538 F. 2d 704, 710 (CA5 1976); id., at 711 (Tuttle, J., concurring); United States v. Plante, 472 F. 2d 829, 831-832 (CA1), cert. denied, 411 U. S. 950 (1973); United States v. Roland, 449 F. 2d 1281 (CA5 1971); Driver v. United States, 441 F. 2d 276 (CA5 1971); Beasley v. United States, 94 U. S. App. D. C. 406, 218 F. 2d 366 (1954), cert. denied, 349 U. S. 907 (1955). See also United States v. Hoffman, 415 F. 2d 14, 21 (CA7), cert. denied, 396 U. S. 958 (1969) (prosecutor’s closing argument referring to accused as “liar, crook, and wheeler and dealer” was improper but harmless error). If instructions may be found to have cured prosecu-torial error relating to the defendant’s past misconduct beyond a reasonable doubt, they ought surely to be considered in deciding whether to subject a defendant to a second trial because of defense error in referring to past misconduct by the prosecution.
See Tr. of Voir Dire by Defendant’s Counsel 22.
In this respect, the instant case differs markedly from the situation in Thompson v. United States, 155 U. S. 271 (1894), discussed ante, at 512. There, upon discovery that one of the petit jurors had served on the grand jury indicting the defendant, the trial court immediately announced that, “[if it] is insisted on by the gentlemen, there is no way left but for the court to discharge the jury on that ground . . . .” Record in No. 637, O. T. 1893, p. 20. Defense counsel objected to the juror’s participation, but also objected to a discharge of the jury, arguing that he was entitled to an acquittal once having been placed in jeopardy. The trial court was of the view, clearly correct, that had the juror remained on the panel despite counsel’s objection any conviction would have been reversed. Id., at 21-22. That being the case, the trial court held that the jury could be discharged and a new jury impaneled without violating the Double Jeopardy Clause. This Court affirmed.
Thus, while the trial court repeatedly challenged defense counsel on his theories for admissibility of the Arizona Supreme Court’s ruling, see App. 204, 205, 209, 211, 217, 248, not once did the court refer to “manifest necessity”; question defense counsel as to the nature of any curative instructions that might be propounded; or otherwise indicate a consciousness that mere error on either side is insufficient to warrant the grant of a mistrial over defense objections, see n. 4, supra.
“Based upon defense counsel’s remarks in his opening statement concerning the Arizona Supreme Court opinion and its effect for the reasons for the new trial, the motion for mistrial will be granted.” App. 271-272. As was noted in the Court of Appeals, the circumstances of the argument on the mistrial motion and the ruling itself make it “quite possible that the grant of mistrial was based on the fact that the impropriety of counsel’s conduct had been established without reaching the question whether there could, nevertheless, be a fair trial.” 546 F. 2d, at 833 (Merrill, J., concurring).
The majority relies on three aspects of the record to support its conclusion that the trial court did make an evaluation of the prejudicial impact of counsel’s remarks and of the need for a mistrial to correct the error. Ante, at 514-515, n. 34, 517 n. 39. The first is that the trial court was aware of the double jeopardy consequences of an improvidently granted mistrial, namely, that the defendant may not be tried again. While this *524ts true, none of the comments by the court suggests a concern with the propriety of anything other than its ruling on the evidentiary question. See App. 225, 253. Second, the majority points to the fact that counsel each argued whether the prejudice could be cured by means other than a mistrial. But such argument occupied only a minuscule portion of each side’s discussion and elicited no comment or response from the court.
Finally, the Court notes that at the voir dire of the jury, the trial court expressed concern about “poisoning of the panel” and that to allay this concern, the jury was questioned as to its knowledge of the reasons for a new trial. The transcript of the voir dire, however, suggests that this questioning had two purposes: to determine whether any jurors knew why there was a second trial, and to determine whether such knowledge would prejudice them in their deliberations. Tr. of Voir Dire, supra, at 35. Since no jurors knew of the reason for the new trial, no inquiry was made as to prejudice — recognized at this time by the court and by counsel as a separate issue. None of these portions of the record establishes that the trial court at any time made a determination that the prejudice from counsel’s opening statement could not be cured by an instruction, or that the court had any basis, such as through a voir dire, on which to make such a determination.
See, e. g., Thompson v. United States, discussed ante, at 512, and in n. 7, supra. Although not every error that would require reversal upon conviction necessitates a mistrial, frequently the “high degree of necessity” required by the Perez doctrine is present, and may be implied from the record if not expressed thereon, when an error of such magnitude prompts a mistrial. See Illinois v. Somerville, 410 U. S. 458, 477-483 (1973) (Marshall, J., dissenting).
Moreover, given the wide variety of situations in which it may be appropriate to grant a mistrial, and the difficulty in setting forth a single *526standard that can provide meaningful guidance on each occasion, a statement of reasons by the trial court would contribute to the development of a body of rules, precedents, and principles that might be useful in providing guidance to other courts. Cf. United States ex rel. Johnson v. Chairman of N. Y. State Bd. of Parole, 500 F. 2d 925, 928-934 (CA2), vacated as moot, 419 U. S. 1015 (1974).
Given the importance of respondent's constitutionally protected interest in avoiding unnecessary second trials, United States v. Jorn, 400 U. S., at 486, it might even be argued that a statement of reasons explicitly relating to the need for a mistrial is always required. I do not go this far here, but only observe that we have held in numerous contexts that governmental decisionmakers must state their reasons for decision, particularly where the decision is adverse to the constitutionally or statutorily protected interests of an individual. See, e. g., Morrissey v. Brewer, 408 U. S. 471, 489 (1972); Goldberg v. Kelly, 397 U. S. 254, 271 (1970).
In Simmons v. United States, 142 U. S. 148 (1891), discussed ante, at 512, the trial court had explained at length the reasons for its conclusion that there was a “manifest necessity” for the mistrial. 142 U. S., at 149-150. Indeed, even in Thompson v. United States, discussed ante, at 512, and in n. 7, supra, the trial court’s finding that there was “no [other] way” to respond to the grand juror’s presence on the petit jury sufficiently indicated on the record an exercise of discretion informed by the “manifest necessity” standard.