I disagree with your fundamental point. An anulment is if there was no marriage to begin with. With a usurper, it would be as if he was never elected. No consumation. As though he snuck into the White House and pretended he was president when no one was looking. Something a delusional child would do. Doesn't deserve the blessings of Liberty or the operation of the Constitution. Just collar the guy after the nearest judge declared an anulment, making sure they didn't steal the silverware on the way out.
There's got to be a first. I see no problem. It would be a logical conclusion, therefor righteous.
Just treat him like you would any other illegal alien.
That's it. End of discussion.
Uh, yea that works, we ignore the constitution to get this done. Isn't that called a coup?