Obama committed a few. Killed reporters in a drone strike, and civilians at other times. Was even forwarded as a warcrime. But wasn't it previously vetoed. Will Biden ordering the drone strike resign? Warcrimes require a nation to be held accountable like the Victor of War taking those committing attrocity into accountability. Otherwise they are pointless exercise. If taken to tribunal at the Hague or the ICC a nation can always withdraw from its rulings like Syria. Then what, some bad publicity, perhaps even a war, or some sanctions, or failed rhetoric. Warcrimes, snore crimes. But occasionally they hang some nazis.