It is one thing to pass a law like this, quite another to enforce it. They’d have to have a super-majority to get something like this passed, assuming everyone on their team would vote for it. Then they’d have to go out and find the guns, assuming they have the will to even try. Once that starts, the US will become scorched earth. There are worse things buried in the ground in this country by its citizenry than the 300 million+ firearms that can be accounted for, much worse.
Even so, pressuring legislators now seems the easier path to enforcing our will. I guess I’d rather do that than have to take more drastic measures later to convince the clowns.