Fifth Amendment to the United States Constitution
The Double Jeopardy clause in the Fifth Amendment forbids a defendant from being tried again on the same (or similar) charges in the same case following a legitimate acquittal or conviction. In common law countries, a defendant may enter a peremptory plea of autrefois acquit or autrefois convict (autrefois means "in the past" in French). It means if the defendant has been acquitted or convicted of the same offence and cannot be retried under the principle of double jeopardy. The original intent of the clause is to prevent an individual to go through a number of prosecutions for the same act until the prosecutor gets a conviction.