> a sovereign state governs itself and is not governed by others

Hence, if anyone commits a crime in another country, they fall under the jurisdiction of that country. So while the US doesn't have to recognize the ICC, listen to it, or follow its verdicts, other countries are free to do so.

But now the US is threatening the judges of the ICC, which is hypocritical to say the least. It's more of a mafia thing, really. Not surprising, given Trump's background.