I mean no, I do not believe the US military is going to invade the Vatican and install an anti-pope.
But also? I need you to understand that you are being lead by people who consider historical events like that "awesome," and more or less every moment of human history post-Enlightenment a "mistake."
So they are serious about threatening the Pope. That's real. This is how these guys roll. I highly doubt the US military could be brought to bear to DO IT, but they are being serious.