on the contrary, even China would retaliate. It's the american equivalent of going into a texas bar and shooting a clip. You are now a proven reckless danger to everyone else and they will retaliate at once in your direction, regardless of if you were being stupid or had a specific target.

They do that because the alternative is a shootout at everone and many people in the bar will die. No single person/country is going to take those odds in an era where there are thousands of nuclear warheads now.