If we “nuked just one country” the rest of the world would fear us. Good idea! Then they’d talk about us and agree that something needed to be put in place to counter us. They’d strengthen the UN into exactly the kind of world government with a military and taxes that we fight against. They’d consider us a renegade state, grow sympathetic to our enemies in the war on terrorism, and we’d be given the run around as we demanded their assistance in rooting out members that we think are in their country. We’d be as isolated as France, and there are nuclear states that would probably take advantage of such a shift in world opinion to respond to any further “aggression” by us on their new allies, not to mention how many new nuclear powers would be created after such a display. That's not the world we want to live in.