On a theoretical Biden EO,
Congress, as currently assembled, likely couldn't block it. That leaves judicial review. Judicial review takes time. Presidents have ignored stays before this and will do so again. What's going to happen? Will Biden be arrested? We already know that doesn't happen.
ETA: I would bet my life that most of those in and around the apparatus of power would ultimately concede (though loudly) many issues we're currently paralyzed on to maintain the sacrosanctity of the Presidency. And it would be a brilliant stroke of using the corrupt, patronage seeking nature of the system against itself.
This precise issue is about guns and innocent children, yes. But it takes place in the context of a power struggle. When your opponent is operating along the doctrine of "we intend to accumulate power to ourselves and deny it to others" and are making great strides at repeatedly demonstrating that even with technical statutory authority, you are ineffective and weak, then it is time to stop "playing by the rules." The way to dissuade an opponent from engaging in a naked power struggle is to meet them on those terms. Make their attempts to do so have real consequences. Watching them accumulate it all while showing everyone which section and clause prevents us from action suits them just fine.
The "flipping the chess board over" analogy is a popular one. I no longer find it accurate. Our opponents are blatantly cheating and smirking across the board at us while we continue to play "correctly." It isn't at all unexpected that some significant portion of the patrons watching (who, for the sake of this analogy actually have many of their needs, if not their very lives riding on the outcome, the players not so much) might grow resentful at the player they are depending on as the game drags on and there we are, just losing the game. Repeatedly pointing out how unfair it is doesnt impress anyone with skin in the game. In that context, flipping the board over and punching the ass in the face is not the egregious act it might otherwise be.
Emergency powers are rather broad.
We've been under state of emergency with respect to Iran for my entire 43 years on this Earth.
We're under something like 30 states of emergency right this minute. Somehow, despite the numerous suspensions of various swathes of codes and statutes, the foundations of our institutions haven't sunk into the abyss.
I think there's a rather plain case for "compelling government interest" at this point. Certainly we could have a robust debate about "least restrictive means." Maybe we'll have to give some guns back.
What "honor" is there in upholding institutional virtues that allow this carnage? Why are we still staring at the board trying to figure out where to move our queen if they get to take her out with any piece they choose from any square they choose because they say so?
I bristle at the "omg the militant/fringe/radical left" stuff that floats around, of course. I'm plenty aware of the kookery, though, after a long exhaustive march through 19th century enlightenment and the formations of modern (small "r") republican nation-state politics. But I'm no more impressed either by comfortable liberal moderates more beholden to esoteric principles and "orderliness" than real, immediate suffering. And I say that as someone with a neurotic preference for routines and task-orientation, if not downright undiagnosed ASD.
This country has long been hewn towards human and civil rights taking a back seat to property and status. Guns are property. Property values and investments might take a dive if "unrest" occurs. It is absolutely true that many, far too many, of us will put children on the altar of stability and peace (or at least peaceful enclaves "where I can afford to live, but thats because I've earned it").
It's the same argument King made about those who would espouse support for civil rights, but then be so very "concerned" that it was all done "properly" and not cause disruptions or inconvenience to them.