Eh, you might find the Italians alone have convicted more than one of them.
While they have a de facto immunity based on the unwillingness of the US Government to obey any law, and the military superiority associated with a military budget no one else comes close to. Operations like that are often clearly illegal and in some cases there is even an obligation to prosecute. But in the real world it is rarely pursued because there is no practical way to enforce a judgement, and courts are well aware that pronouncing judgements they cannot enforce just tends to make them look weaker.
But any student of history would tell you this is a very dangerous course for the US Government to be taking. It's hard to see much upside to it to begin with, and the downside is really a national poison. We have already poisoned our relations with friendly nations all around the world, and it appears to be our policy to simply continue doing so. One day, and we can argue over how long, but one day inevitably we wont be the hyperpower anymore, we wont be able to get away with this, and worse yet, the other players, some of whom will be in really good positions to mess with us... they are ALL going to hate our guts.
This is just viciously poor strategy.