Double Jeopardy - When Jeopardy Attaches

Courts have provided much clearer guidance on the question of when jeopardy attaches, or begins. This question is crucial to answer because any action taken by the government before jeopardy attaches, such as dismissal of the indictment, will not prevent later proceedings against a person for the same offense. Once jeopardy has attached, the full panoply of protection against multiple prosecutions and punishments takes hold.

The U.S. Supreme Court has held that jeopardy attaches during a jury trial when the jury is empanelled. In criminal cases tried by a judge without a jury, jeopardy attaches when the first witness is sworn. Jeopardy begins in juvenile-delinquency adjudications when the court first hears evidence. If the defendant or juvenile enters a plea agreement with the prosecution, jeopardy does not attach until the court accepts the plea.