I wonder what would happen if by some bizarre twist of fate they accidentally nuked Florida? As in, same scenario but someone forgot to take a nuclear warhead o

I wonder what would happen if by some bizarre twist of fate they accidentally nuked Florida? As in, same scenario but someone forgot to take a nuclear warhead off first. Even if it was a demonstrable accident, a stupid number of people would still die. Would America be somewhat obliged to retaliate, even if just to show the rest of the world that they don't have a free pass to pull off an 'accident' of their own? If anyone wants to turn this into a book, I'll buy it!