I have a right to assert someone has committed War Crimes, when I've indicated IMO too, which I've done numerous times directed at Obama, Hillary, AND Bush. Cheney was VP, so he technically was not in authority positions to order anything done. (But I do think Cheney would commit War Crimes too, if he was given the opportunity to order it under proper authority. That could not be done as VP.)
Look, we can't prosecute any of these people in a court of law, this goes all the way back to Vietnam, but we can "prove" by history what they did do. That's what I mean by "proven", again, IMO.