Tadić Decision

The Tadić Decision refers most prominently to the Prosecutor v. Duško Tadić Interlocutory Appeal on Jurisdiction issued by the Appeals Chamber of the International Criminal Tribunal for the former Yugoslavia (ICTY) on 2 October 1995. Tadić, a Bosnian Serb, challenged the tribunal's authority to try him for acts committed at the Omarska and Keraterm camps. The Appeals Chamber, presided over by Antonio Cassese, rejected the challenge and in doing so produced one of the most cited rulings in modern international criminal law.

Three contributions stand out:

• Definition of armed conflict. The Chamber held that an armed conflict exists "whenever there is a resort to armed force between States or protracted armed violence between governmental authorities and organized armed groups or between such groups within a State." This formula is now the working test used by international courts and the ICRC.
• Collapsing the international/non-international divide. The Chamber found that customary international law imposes individual criminal responsibility for serious violations of the laws of war committed in non-international conflicts, not just inter-state wars — a major expansion of the reach of IHL.
• Legality of the tribunal itself. It confirmed that the UN Security Council could lawfully create a criminal tribunal under Chapter VII of the UN Charter (Resolution 827, 1993).

A separate 1999 Tadić Appeals Judgment is also frequently cited for articulating the "overall control" test for attributing the conduct of armed groups to a state — a standard that diverged from the ICJ's stricter "effective control" test in Nicaragua v. United States (1986) and was revisited by the ICJ in Bosnia v. Serbia (2007).

Together, the Tadić rulings shaped the jurisprudence of the ICTR, the Special Court for Sierra Leone, and the International Criminal Court, particularly in defining war crimes under Article 8 of the Rome Statute.