Anyone from a nation that signed the Statute of Rome. Guess what, USA not only hasn't joined the ICJ but has historical laws in place that will make them intervene even with military force to free a US citizen in the hands of the ICJ.
That isn't how the Statute of Rome works. The Statute of Rome applies to things done on the territory of signatories.
So if a US person has operated in the territory of a signatory, and committed something suspected to be a covered crime, and there is no US attempt to prosecute them, they can be prosecuted.
The US militarily can't intervene. They don't have the capacity to fight the Dutch, or French or the like, and the political cost of attacking other NATO countries is of course enormous-- it would be the end of the US as a superpower and lead to an actual EU-US war which would probably last for decades. There's a reason the US Servicemen Protection Act has an out, that it doesn't require any action. Think of it, not as a real policy, but as a dog making sure there's a fence between it and another dog before it starts barking.
*ICC(International Criminal Court aka Hague established 1998/2002) not the ICJ(International Court of Justice aka World Court established 1946) they are different entities , hence the Hague Invasion Act from the US.
