One of the core protections for criminal defendants is the double jeopardy rule provided by the Fifth Amendment to the U.S. Constitution. The short version of the rule is that you cannot be prosecuted more than once for the same crime. It prevents prosecution for the same crime after an acquittal or a conviction, and it also prevents imposing multiple punishments for the same crime. However, double jeopardy becomes much more complex in some circumstances.
The obvious application of double jeopardy is when law enforcement finds new evidence of the defendant’s guilt after the jury has already acquitted them. The prosecution cannot charge them again, even if the evidence shows that they probably are guilty. Another situation in which double jeopardy is clear is when a judge tries to sentence a defendant for a crime for which they have already served their sentence.
Limitations on Double Jeopardy
The protection applies only to criminal cases, so a defendant who was acquitted or convicted of a crime may be sued in a civil lawsuit based on the same conduct. They also can face administrative proceedings arising from the same incident, such as the suspension or revocation of their driver’s license. Also, double jeopardy does not apply to prosecutions for lesser included offenses if the defendant already has defeated the charge of the more serious offense. (Read more here about what lesser included offenses are.) However, if a jury convicts a defendant of multiple charges based on the same conduct, the judge can impose a sentence only for the greater crime. Convictions for assault and aggravated assault, for example, will result in a sentence only for aggravated assault.
Double jeopardy does not attach until the court swears in the jury, or until the first witness starts to testify in a trial before a judge. Filing charges thus does not trigger the rule.
The federal and state governments can prosecute a defendant separately for the same conduct without violating the double jeopardy rule. Multiple states also can pursue separate prosecutions. Protection attaches only for prosecutions by the same sovereign. The dual sovereignty rule means that a defendant can face prosecution by both the state and the federal government, although often one will defer to the other. The federal government may have a right to prosecute a crime that did not cross state boundaries, occur on federal property, or violate a specific federal law, as long as it had some connection to interstate commerce or another area controlled by the federal government.
Jeopardy needs to terminate before the double jeopardy rule can be violated. In other words, if jeopardy remains continuous, this still is “single jeopardy” and constitutionally valid. Jeopardy usually terminates when a case ends, such as when a jury returns a verdict or when a judge enters a judgment of acquittal or dismisses the charges.
In some situations, the prosecution may proceed with a retrial after the case ends without violating the double jeopardy rule. This is common when there is a hung jury or when a judge declares a mistrial. If the defense objects to the mistrial, the prosecution will not be able to retry the defendant unless it shows that there is a critical need to proceed with the retrial. (A critical need is not a demanding standard in this context, though, and even the absence of a juror may support a retrial over a defense objection.) At other times, the defendant may consent to a mistrial, which gives the prosecution an automatic right to retry the case in most situations.