As with any other international body, the ICC and its authority depend on the cooperation of its members. And so far, the track record of the major powers at the ICC suggests that their commitment to seeing perpetrators prosecuted has been lacking.
Gaza: Indiscriminate Israeli War Crimes against Civilians. Egypt: A Brutal Military Coup To Halt Democracy and Silence Political Dissent. Syria: a Bloody Civil War Fueled by Sectarianism and Foreign Interference.