> True, true, but somehow that's never been much of an obstacle to totalitarian governments. Somehow there's always a soldier who will push the button.

Actually, the unwillingness of the Red Army to do any more invasions was arguably the precipitating factor in the fall of the Soviet empire. In 1988, Gorbachev gave a speech to the Warsaw pact meeting where he told them that the Brezhnev doctrine was no more. No socialist government would be able any longer to count on Russian aid in putting down popular uprisings. A year later, the empire crumbled. Of course, it wasn't the soldiers per se who refused, but the generals who were afraid of the potential mutinies (and the occasional actual ones).