Non Bis in Idem

Non bis in idem (Latin: "not twice for the same") is a procedural safeguard recognised across most domestic legal systems and in international criminal law. It prevents repeated prosecution or punishment of an individual for conduct for which they have already been finally convicted or acquitted. The principle protects legal certainty, judicial economy, and the rights of the accused against state harassment.

In international human rights instruments, the rule appears in Article 14(7) of the International Covenant on Civil and Political Rights (ICCPR), which prohibits being "tried or punished again for an offence for which he has already been finally convicted or acquitted in accordance with the law and penal procedure of each country." A similar provision is found in Article 4 of Protocol No. 7 to the European Convention on Human Rights (ECHR) and Article 8(4) of the American Convention on Human Rights.

In international criminal law, the principle is codified in:

• Article 20 of the Rome Statute of the International Criminal Court (1998), which prevents the ICC from re-trying a person already tried by the Court or, with limited exceptions, by another court.
• Article 10 of the ICTY Statute and Article 9 of the ICTR Statute, both containing comparable provisions.

A key limitation is the "same conduct" test: the principle generally applies only within a single jurisdiction, and most systems do not bar re-prosecution in a different state for the same acts unless treaty law (such as Article 54 of the Schengen Convention within the EU) provides otherwise. The Rome Statute also carves out exceptions where prior proceedings shielded the accused or were not conducted independently and impartially — a safeguard tied to the ICC's complementarity regime.

The rule does not bar civil suits arising from the same facts, nor disciplinary proceedings distinct in nature from criminal punishment.