The legal term double jeopardy refers to a second prosecution of an individual for an offence for which he has already been prosecuted. Double jeopardy is famously prohibited in the Fifth Amendment of the United States constitution, which states that no person shall, “be subject for the same offence to be twice put in jeopardy of life or limb.” Not only does the double jeopardy doctrine uphold the finality of criminal proceedings, it also protects individuals from the stress of multiple prosecutions. Despite dating back to Roman times, this legal rule is often challenged. Some legal reform advocates believe that a second trial should be permitted if significant new evidence becomes available – for example DNA evidence can reveal more using more recent technology. Double jeopardy laws are intended to protect innocent people from continual harassment by the state. They also prevent a defendant from receiving successive trials for the same offence – for instance, someone found guilty of murder cannot also be tried for manslaughter for the same act. Some exceptions exist. A new trial is allowed if the original trial is declared a mistrial, or if an appeal against a conviction is successful. The rules also do not restrict a different sovereignty from prosecuting for the same offence. Similarly, in the United States, civil proceedings can be brought against someone who has already been acquitted or convicted of committing the offence.