The US signed the Rome Statute, but never ratified it.
Once a country ratifies the statute, it's in until a year after it gives notice to quit. And, even then, quitting has no effect on investigations already in progress.
You can get out even if you ratify the statue, membership is basically "as long as you want" and the US' way of handling the ICC has been nothing but a farce, threatening them everytime some US soldier is investigated for war crimes.
And the US still refuses to pay those reparations.
