Well, I imagine whatever they fired at will blow up. Then that's pretty much it until they fire the next one. Rinse, repeat, Putin get the fuck out of Ukraine.
I mean.....the whole reason to care about permission was so they could get further future support. They aren't getting that. If on Jan 21st they discover this whole other set of rockets they recieved from the USA in the past, and forgot about, why NOT use them??? Oh, they don't have USA's support. Ok, what's going to happen if they use them on Jan 21st? They'll endanger their non-existant support? Ok. FIRE!!!
UA needs US and/or EU satellite controls in order to carry out the long range strikes. If permission is revoked, they can't simply pick up their ball and go home to play.
WHAT'S THAT? I CANT HEAR YOU OVER THE SOUND OF THESE KICKASS ROCKETS WE ARE SENDING INTO RUSSIA. ALSO, TELL JOE THANKS FOR THEM BECAUSE WE FIGURED OUT HOW TO MAKE THEM. NOW WE ARE MAKING OUR OWN. COOL YEAH?
I guess, but also it doesn't really change anything at this point. We can't allow nuclear threats to be some Carte blanche that can be used to get your way. We need to resist and make clear that Russia has nothing to win in Ukraine. The opposite would be the true escalation and actors like China, North korea, Iran etc. would instantly try to copy this strategy. If Putin wants to pull the trigger that is on him only and either way I'd much rather we put a stop to it now before this idea of going nuclear establishes any further.
This would be the end of Russia really fast, Putin included. I don't think they are stupid or suicidal on that level. And they have threatened to go nuclear for years now, there's little reason to believe that this time is any different. And ultimately it also doesn't change anything, we can't let Russia bully us with their nuclear threats. Because there will never be an end and if they could conquer the world with nuclear threats they would do so. So let them prepare their missle and have nuclear drills. And send more long range missiles (looking at you Taurus).
I doubt Putin will press the red button. Even Xi Jinping gets irritated whenever Putin threatens with nuclear weapons and tells him to stop with the obvious bluff.
Using nukes even against Ukraine will literally piss everyone off. It will make Russia even more pariah.