The constitutional status of the double jeopardy principle

The principle of double jeopardy operates as a proscription against retrials for the same criminal offence following a trial on the merits by a court of competent criminal jurisdiction concluding in an acquittal or conviction. The principle developed at common law in response to the draconian punishments traditionally imposed on defendants and the deficiencies in medieval criminal procedure to the advantage of the prosecution. The common law immunity from reprosecution gradually developed in response to the injustice in permitting retrials for the same offence following an acquittal or conviction. The principle was also designed to prevent the imposition of multiple punishments for the same criminal transgression in separate proceedings.