Knowing this, in the scenario that the United States flouts international law and permits Netanyahu to visit Washington DC again...the ICC would refer the case to the UNSC, where the US is a permanent member with veto power. Yeah that's going to deter them :)
The only possible real deterrence for the United States is the international reputation stain that would come with being referred to as a state that provided a safe haven for war criminals with international arrest warrants.