Um...and you think the US doesn't have its own Yamantau?
Cheyenne Mountain may not be up to scratch any more, but what about Looking Glass and the whole system set up to insure continuity of command during the Cold War?
Remind me where the President was in the immediate aftermath of 9/11?
Remind me what is in the briefcase that is carried by this guy?
If you think the US would surrender just because of some fantasy dislike of the current President, then I think you are allowing your political inclinations to cloud the practical picture.
Long story short, they can't get away with it, they have not been able to get away with it since 1945 and they're not likely to be able to get away with it any time in the future.