BRENNAN, J., dissenting 437 U.S. lay had so prejudiced respondent's defense as to precludeconsistently with the Due Process Clause-his conviction of the offense alleged in count one of the indictment. He therefore dismissed this count with prejudice. Under the principles of double jeopardy law that controlled until today, further prosecution of respondent under count one would unquestionably be prohibited, and appeal by the United States from the judgment of dismissal thus would not lie. See 18 U. S. C. § 3731 (1976 ed.). The dismissal would, under prior law, have been treated as an "acquittal"-i. e., "a legal determination on the basis of facts adduced at the trial relating to the general issue of the case." United States v. Martin Linen Supply Co., 430 U. S. 564, 575 (1977) (citations omitted). Indeed, further proceedings would have been barred even if the dismissal could not have been so characterized. United States v. Jenkins, 420 U. S. 358 (1975), established that, even if a midtrial termination does not amount to an "acquittal," an appeal by the United States from the dismissal would not lie if a reversal would, as is of course true in the present case, require "further proceedings of some sort, devoted to the resolution of factual issues going to the elements of the offense charged." Id., at 370. This principle was reaffirmed only last Term in Lee v. United States, 432 U. S. 23, 30 (1977): "Where a midtrial dismissal is granted on the ground, correct or not, that the defendant simply cannot be convicted of the offense charged, . . . further prosecution is barred by the Double Jeopardy Clause." 1 But the Court today overrules the principle recognized in Jenkins and Lee. While reaffirming that the Government may not appeal from judgments of "acquittal" when reversals would require new trials, the Court holds that appeals by the United States will lie from all other final judgments favor 1 See also Finch v. United States, 433 U. S. 676 (1977) (applying rule of Jenkins to dismissal entered on basis of stipulated facts); United States v. Martin Linen Supply Co., 430 U. S. 564 (1977). 82 BRENNAN, J., dissenting able to the accused. The Court implements this new rule by fashioning a more restrictive definition of "acquittal" than heretofore followed-i. e., "a resolution, correct or not, of some or all of the factual elements of the offense"-and holds, without explanation, that, under that restrictive definition, respondent was not "acquitted" when the District Judge concluded that the facts adduced at trial established that unjustifiable and prejudicial preindictment delay gave respondent a complete defense to the charges contained in count one. I dissent. I would not overrule the rule announced in Jenkins and reaffirmed in Lee. This principle is vital to the implementation of the values protected by the Double Jeopardy Clause; indeed, it follows necessarily from the very rule the Court today reaffirms. The Court's attempt to draw a distinction between "true acquittals" and other final judgments favorable to the accused, quite simply, is unsupportable in either logic or policy. Equally fundamental, the decision today indefensibly adopts an overly restrictive definition of "acquittal." Its definition, moreover, in sharp contrast to the rule of Jenkins, is incapable of principled application. That is vividly evident in the Court's own distinction between a dismissal based on a finding of preaccusation delay violative of due process, and a dismissal based upon evidence adduced at trial in support of a defense of insanity or of entrapment. Ante, at 97-98. Why should the dismissal in the latter cases raise a double jeopardy bar, but the dismissal based on preaccusation delay not also raise that bar to a retrial? The Court ventures no persuasive explanation. Because the thousands of state and federal judges who must apply today's decision to similar "affirmative defenses" are left without meaningful guidance, only confusion can result from today's decision. I The Court reaffirms the "most fundamental rule in the history of double jeopardy jurisprudence": that judgments of BRENNAN, J., dissenting 437 U.S. acquittal, no matter how erroneous, bar any retrial and thus that, under the proviso in 18 U. S. C. § 3731 (1976 ed.),2 appeals by the United States will not lie when reversal would require a retrial. The major premise for the Court's conclusion that the Government may appeal from the final judgment entered for respondent is that there is a difference of constitutional magnitude between "acquittals" and midtrial dismissals, entered on motion of the accused, on grounds "unrelated to factual innocence." This premise is fatally flawed. It, quite simply, misconceives the whole basis for the rule that "acquittals" bar retrials. The reason for this rule is not, as the Court suggests, primarily to safeguard determinations of innocence; rather, it is that a retrial following a final judgment for the accused necessarily threatens intolerable interference with the constitutional policy against multiple trials. Moreover, in terms of the practical operation of the adversary process, there is actually no difference between a so-called "true acquittal" and the termination in this case favorably to respondent. A While the Double Jeopardy Clause often has the effect of protecting the accused's interest in the finality of particular favorable determinations, this is not its objective. For the Clause often permits Government appeals from final judgments favorable to the accused. See United States v. Wilson, 420 U. S. 332 (1975) (whether or not final judgment was an acquittal, Government may appeal if reversal would not ne 2 Section 3731 provides that the United States may obtain appellate review of a "dismissal" "except that no appeal shall lie where the double jeopardy clause of the United States Constitution prohibits further prosecution." 3 The Court cites with approval Sanabria v. United States, ante, p. 54; United States v. Martin Linen Supply Co., supra; Fong Foo v. United States, 369 U. S. 141 (1962); Kepner v. United States, 195 U. S. 100 (1904); and United States v. Ball, 163 U. S. 662 (1896). 82 BRENNAN, J., dissenting cessitate a retrial). The purpose of the Clause, which the Court today fails sufficiently to appreciate, is to protect the accused against the agony and risks attendant upon undergoing more than one criminal trial for any single offense. See ibid. A retrial increases the financial and emotional burden that any criminal trial represents for the accused, prolongs the period of the unresolved accusation of wrongdoing, and enhances the risk that an innocent defendant may be convicted.* See Arizona v. Washington, 434 U. S. 497, 503–504 (1978); Green v. United States, 355 U. S. 184, 187-188 (1957). Society's "willingness to limit the Government to a single criminal proceeding to vindicate its very vital interest in enforcement of criminal laws" bespeaks society's recognition of the gross unfairness of requiring the accused to undergo the strain and agony of more than one trial for any single offense. United States v. Jorn, 400 U. S. 470, 479 (1971) (opinion of Harlan, J.). Accordingly, the policies of the Double Jeopardy Clause mandate that the Government be afforded but one complete opportunity to convict an accused and that when the first proceeding terminates in a final judgment favorable to the defendant any retrial be barred. The rule as to acquittals can only be understood as simply an application of this larger principle. Judgments of acquittal normally result from jury or bench There are a number of reasons a retrial enhances the risk that "even though innocent, [the criminal defendant] may be found guilty." Green v. United States, 355 U. S. 184, 188 (1957). A retrial affords the Government the opportunity to re-examine the weaknesses of its first presentation in order to strengthen the second. And, as would any litigant, the Government has been known to take advantage of this opportunity. It is not uncommon to find that prosecution witnesses change their testimony, not always subtly, at second trials. See Arizona v. Washington, 434 U. S. 497, 504 n. 14 (1978), quoting Carsey v. United States, 129 U. S. App. D. C. 205, 208-209, 392 F. 2d 810, 813-814 (1967). "By "final judgment favorable to the accused," I am, of course, referring to an order terminating all prosecution of the defendant on the ground he "simply cannot be convicted of the offense charged." See Lee v. United States, 432 U. S. 23, 30 (1977). BRENNAN, J., dissenting 437 U.S. verdicts of not guilty. In such cases, the acquittal represents the factfinder's conclusion that, under the controlling legal principles, the evidence does not establish that the defendant can be convicted of the offense charged in the indictment. But the judgment does not necessarily establish the criminal defendant's lack of criminal culpability; the acquittal may result from erroneous evidentiary rulings or erroneous interpretations of governing legal principles induced by the defense. Yet the Double Jeopardy Clause bars a second trial. In repeatedly holding that the Government may not appeal from an acquittal if a reversal would necessitate a retrial, the Court has, of course, recognized that this rule impairs to some degree the Government's interest in enforcing its criminal laws. Yet, while we have acknowledged that permitting review of acquittals would avoid release of guilty defendants. who benefited from "error, irrational behavior, or prejudice on the part of the trial judge," United States v. Martin Linen Supply Co., 430 U. S., at 574; see United States v. Wilson, supra, at 352, we nevertheless have consistently held that the Double Jeopardy Clause bars any appellate review in such circumstances. The reason is not that the first trial established the defendant's factual innocence, but rather that the second trial would present all the untoward consequences the Clause was designed to prevent. The Government would be allowed to seek to persuade a second trier of fact of the defendant's guilt, to strengthen any weaknesses in its first presentation, and to subject the defendant to the expense and anxiety of a second trial. See ibid. This basic principle of double jeopardy law has heretofore applied not only to acquittals based on the verdict of the factfinder, but also to acquittals entered by the trial judge, following the presentation of evidence but before verdict, pursuant to Fed. Rule Crim. Proc. 29. See Sanabria v. United States, ante, p. 54; United States v. Martin Linen Supply Co., |