Nothing would change, the rhetoric that it is all our fault would be increased.
I hope you are wrong, but cannot claim that you are. It would seem that if they actually lit off anything with nuclear materal, saner minds would finally start to push back on those who would love to see our Nation destroyed. It would allow a huge opening for a lot of the People to stir to action and add to that push.
On the other hand, entropy does seem to dictate that your scenario is likely.