Ne Bis in Idem in International Law

Abstract

The principle that a person should not be prosecuted more than once for the same criminal conduct, expressed in the maxim ne bis in idem and also referred to as the rule against double jeopardy, is prevalent among the legal systems of the world. The rule is the criminal law application of a broader principle, aimed at protecting the finality of judgments, encapsulated in the doctrine res judicata. To date, the thrust of opinion among writers denies that the principle of ne bis in idem can be recognized either as a rule of custom or a general principle of international law; in this regard, the most commonly argued objection to a recognition of the rule is the disparities of approach to it in different legal systems. This article argues that a core of double jeopardy protection can be identified from the different approaches to the principle to be found in different legal systems. These elements of the principle could form the basis of a future international or erga omnes/inter-state ne bis in idem principle, whether as a rule of custom or general principle of law. First, the background, context, and rationale of the rule are outlined and discussed. The actual practice of the principle in the international legal order is then considered. Finally, elements of a potential international rule of custom or a general principle of international law are proposed and justified.

Keywords: Ne bis in idem, criminal procedure, international law, international criminal law

JEL Classification: K10, K14, K33, K42