On 11 June 2010, the first Review Conference of the International Criminal Court (ICC) adopted Resolution RC/Res. 6 on the ‘Crime of Aggression’ by consensus, after years of debates and negotiations in the framework of the Preparatory Commission for the International Criminal Court and the Special Working Group on the Crime of Aggression. The resolution includes a definition of the crime of aggression and the conditions under which the Court could exercise jurisdiction with respect to the crime, while making the actual exercise of jurisdiction ‘subject to a decision to be taken after 1 January 2017’ by states parties. This outcome has triggered a broad variety of reactions. The UN praised it as a ‘historic agreement’ and a significant step towards a new ‘age of accountability’. Some non-governmental organizations (NGOs) have expressed concerns that the compromise deepens the gaps between states and leaves accountability loopholes. US legal advisor Harold Koh qualified the compromise as an opportunity for further constructive dialogue and positive engagement with the ICC.