Bush jr pulled us out of the International court (ICC) as one of his first acts when he was "elected" back in 2000. Obama ignored the issue when he could have reinstated the US (when he had a majority in both houses) and of course Trump would never recognize the ICC.
So it looked like the US was going to get away with its war crimes in Afghanistan. However, Afghanistan is a member of the ICC and when the prosecutor started to look into the war crimes it was with Afghanistan's blessings.
So now the US can be held accountable for our war crimes in Afghanistan even if we have not signed on to recognize the court. Bad news for the US but good news for justice.
Of course the Trump administration is vehemently opposed to any scrutiny by the ICC -- the US believes it is not accountable to anyone, nevertheless the ICC. And so the bullying begins.....or I guess I should say, the bullying continues.
More here.