It's not a question of whether they can be tried and convicted; they can and have been tried by foreign courts throughout our history.
The idea that US troops are immune from international law is not going to serve us well in the 21st century. No nation's sovereignty extends that far. Unless, of course, we want to take over the entire planet...
Who's up for invading China and India and then occupying them for three or four hundred years if we manage to beat them? :down: