The Four Core Crimes
Genocide, war crimes, crimes against humanity, and aggression: what each crime means and how they differ.
Genocide
Genocide, as defined in Article 6 of the Rome Statute, is the commission of certain acts with the intent to destroy, in whole or in part, a national, ethnical, racial, or religious group. The acts include killing members of the group, causing serious bodily or mental harm, deliberately inflicting conditions calculated to bring about physical destruction, imposing measures to prevent births, and forcibly transferring children.
The critical element is specific intent (dolus specialis): the perpetrator must intend to destroy the group as such, not merely kill individuals who happen to belong to it. This makes genocide the hardest crime to prove. Mass killing alone is not genocide if the intent is political rather than group-destructive. The ICTY struggled with this distinction in Bosnia, ultimately finding genocide only at Srebrenica, where the intent to destroy Bosnian Muslims in that area was established.