Nothing about the ICC stops the US from executing war criminals.

https://en.wikipedia.org/wiki/International_Criminal_Court

> The ICC is intended to complement, not replace, national judicial systems; it can exercise its jurisdiction only when national courts are unwilling or unable to prosecute criminals.

Has the US ever executed an American soldier war criminal?

https://en.wikipedia.org/wiki/John_E._Day

Interesting. Thanks for posting that. I hope the US will always prosecute war crimes of its own soldiers, but I'm skeptical--I don't think that's how war and power work.

Oh, I'm skeptical as well.

https://en.wikipedia.org/wiki/Eddie_Gallagher_(Navy_SEAL) is more the norm.