In the legal context, jeopardy refers to the danger of conviction that a defendant is subjected to when on trial for a crime. Jeopardy attaches when a jury is sworn in or, if there is no jury, when a judge begins to hear evidence. Understanding this concept is important because the Fifth Amendment to the U.S. Constitution prohibits double jeopardy, which occurs when a defendant is tried twice for the same crime.

Determining when jeopardy terminates is no less important than determining when it begins, but it's a little more complicated. Once jeopardy has terminated, the government cannot detain someone for additional court proceedings on the same matter without raising double jeopardy questions. If jeopardy does not terminate at the conclusion of one proceeding, jeopardy is said to be "continuing," and further criminal proceedings are permitted.

Jeopardy can terminate in four instances: acquittal, dismissal, mistrial, and appeals. While an acquittal will definitively end jeopardy, the circumstances surrounding a dismissal, mistrial, or appeal will effect whether or not jeopardy has ended.

When Double Jeopardy Protection Ends: Acquittal

A jury's verdict of acquittal terminates jeopardy, and verdicts of acquittal cannot be overturned on appeal even if there is overwhelming proof of a defendant's guilt or even if the trial judge committed reversible error in ruling on an issue at some point during the proceedings. This fundamental maxim of double jeopardy jurisprudence entrusts the jury with the power to nullify criminal prosecutions tainted by egregious misconduct on the part of the police, the prosecutor, or the court, a tremendous bulwark against tyranny in a democratic society.

A jury can also implicitly acquit a defendant. If a jury has been instructed by the judge on the elements of a particular crime and a lesser-included offense, and the jury returns a guilty verdict as to the lesser offense but is silent as to the greater offense, re-prosecution for the greater offense is barred by the Double Jeopardy Clause. For example, a jury that has been instructed as to the crimes of first- and second-degree murder will implicitly acquit the defendant of first-degree murder by returning a guilty verdict only as to murder in the second degree. A not guilty verdict as to the greater offense is inferred from the jury's silence.

When Double Jeopardy Protection Ends: Dismissal

Dismissals are granted by the trial court for procedural errors and defects that operate as an absolute barrier to prosecution. For example, the prosecution must establish that a court has jurisdiction over a defendant before prosecution may commence. Failure to establish jurisdiction will normally result in a dismissal upon an objection raised by the defendant. Dismissals may be entered before a jury has been impaneled, during trial, or after conviction, but jeopardy must attach before a dismissal implicates double jeopardy protection.

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 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 held in United States v. Scott that no double jeopardy interest is triggered when defendants obtain a dismissal for reasons unrelated to their guilt or innocence.

When Double Jeopardy Protection Ends: Mistrial

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 reprosecution. Nor will a mistrial preclude reprosecution when it's declared with the defendant's consent. Courts disagree whether a defendant's mere silence is equivalent to consent.

A different situation is presented when a mistrial is declared over the defendant's objection. In this instance, reprosecution will be allowed only if the mistrial resulted from "manifest necessity," a standard more rigorous than "reasonably necessary" but less stringent than "absolutely necessary." Basically, a mistrial that could've 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 caused by the defendant. Manifest necessity isn't 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.

When Double Jeopardy Protection Ends: Appeal

Every defendant has the right to at least one appeal after conviction. If the conviction is reversed on appeal for insufficient evidence, it's treated as an acquittal and further prosecution is not permitted. However, a defendant may be re-prosecuted when the reversal is not based on lack of evidence. The grounds for such reversals include defective search warrants, unlawful seizure of evidence, and other so-called "technicalities." Retrials in these instances are justified by society's interest in punishing the guilty. Defendants' countervailing interests are considered inferior when a conviction rendered by 12 jurors is overturned for reasons unrelated to guilt or innocence.

The interests of the accused are also lower-ranking when courts permit prosecutors to seek a more severe sentence during the retrial of a defendant whose original conviction was thrown out on appeal. Defendants who appeal their conviction assume the risk that a harsher sentence will be imposed during re-prosecution. However, in most circumstances, courts aren't permitted to impose a death sentence on a defendant during a second trial when the jury recommended life in prison during the first. The recommendation of life imprisonment is construed as an acquittal on the issue of capital punishment.

Are You Protected by Double Jeopardy Laws? Get Professional Help and Find Out

Double jeopardy is a powerful tool for protection against governmental abuse and, if it applies in your case, it can make all the difference. Whether you want to find out if it applies to your case or just want to learn more about the concept, it's best to get in touch with a seasoned criminal defense attorney in your area.