[monocasa]

> That act refers only to the ICC, which is not a sovereign state

The ICC only has authority in territories where a sovereign state grants them authority. Hence the act, a threat to invade a sovereign state if that sovereign state follows the legal process they've legally decided (by signing the Rome statute) and prosecute an American citizen

> and only prosecutes cases that the sovereign states are themselves unwilling to prosecute.

Cases that the sovereign state defers to the ICC as their established legal process.