Once jeopardy attaches, a dismissal granted by the court for insufficient evidence terminates jeopardy and bars further prosecution with one exception. The prosecution may appeal a dismissal entered after the jury has returned a guilty verdict. If the appellate court reverses the dismissal, the guilty verdict can be reinstated without necessitating a second trial. A dismissal granted for lack of evidence after a case has been submitted to a jury, but before a verdict has been reached, may not be appealed by the state.

Reprosecution is permitted and jeopardy continues against the defendant when a case is dismissed by the court at the defendant's request for reasons other than sufficiency of the evidence. For example, courts may dismiss a case when the defendant's right to a speedy trial has been denied by prosecutorial pretrial delay. The Supreme Court has held that no double jeopardy interest is triggered when defendants obtain a dismissal for reasons unrelated to their guilt or innocence (see United States v. Scott, 437 U.S. 82, 98 S.Ct. 2187, 57 L.Ed.2d 65 [1978]).

Mistrials are granted when it has become impracticable or impossible to finish a case. Courts typically declare mistrials when jurors fail to unanimously reach a verdict. Like dismissals, mistrials declared at the defendant's behest will not terminate jeopardy or bar re-prosecution. Nor will a mistrial preclude re-prosecution when it is declared with the defendant's consent. Courts disagree whether a defendant's mere silence is tantamount to consent.

A different situation is presented when a mistrial is declared over the defendant's objection. Reprosecution will be allowed only if the mistrial resulted from "manifest necessity," a standard more rigorous than "reasonably necessary" and less exacting than "absolutely necessary." A mistrial that could have been reasonably avoided will terminate jeopardy, but jeopardy will continue if the mistrial was unavoidable.

The manifest necessity standard has been satisfied where mistrials have resulted from defective indictments, disqualified or deadlocked jurors, and procedural irregularities willfully occasioned by the defendant. Manifest necessity is not present when mistrials result from prosecutorial or judicial manipulation. In each of these cases, courts balance the defendant's interests in finality against society's interest in a fair and just legal system.