Absolutely a KC as applied to US persons. I have no faith or trust in such things, especially if applied to US persons. Way too many competing motives, agendas, allegiances, corruption, etc.

There is no crime over which ICC claims jurisdiction, that the US doesn't have some similar legal remedy. Or if there is, there's a reason we don't (ex. some nations have robust "hate speech" laws, which basically apply to whatever dissent their regime wants to silent). We can (and should) try our own citizens. No interest in World Government, thanks.

Right place and right time, he lucked out.

They decided they needed him as a unifying figurehead to help get the people behind the new government. This despite very strong sentiment amongst the allies that he be treated as a war criminal.

It helped his case that his support for the war had been anemic all along, and that he was actively trying to negotiate surrender terms before Hiroshima.