At 12:20 in the morning on Saturday, June 12, 2010, the Review Conference of the Rome Statute of the International Criminal Court in Kampala, Uganda, adopted by consensus a comprehensive package of amendments on the crime of aggression. States parties to the Rome Statute thereby delivered on their promise, reflected in Article 5 (2) of the Statute, to define the crime of aggression and to agree on the conditions for the Court’s exercise of jurisdiction over that crime. Despite a thorough and more than decadelong preparatory process, few, if any, had predicted such a substantive outcome on the crime of aggression in light of the serious disagreements on major questions, which persisted until the last days of the conference. The key elements of the final package are a definition of the crime of aggression, which limits criminal responsibility to leaders who are responsible for the most serious forms of the illegal use of force between states, and a complicated set of conditions for exercising jurisdiction. Investigations would be based on either a Security Council referral or state consent.