Disclaimer: I have no idea what the right move here is. It's a shitty situation. "How Democracies Die" talks about it in quite a bit of detail, but basically, in the unfolding collapse of a democracy, there's a terrible temptation to start eroding democratic norms "in kind" in response to their eroding from the fascist side, but this is a mistake. You have to keep fighting on the tilted table without trying to tilt it back, because eroding the norms of behavior plays right into the fascists' hands and those democratic standards are horrifyingly hard to get back once you've broken the seal.
But, that being said, keeping in mind that this is satire to make a point: I don't think Biden should have Trump assassinated, or anybody. I do think that it would be a little more directly on the nose if he, as an official act, had Seal Team 6 ambush all the justices that voted for this (as an official act of course), take them with hoods over their heads and in ziptie cuffs to an undisclosed location, and then put up on YouTube the video of someone asking them a few questions in a bare concrete room in that undisclosed location, requesting that they clarify that this is really what they meant. Sort of bring some reality to what is the door they are trying to open, on a personal level, to them. Because I am 100% serious when I say that that is 100% very literally the door they have chosen to open. Sort of a "Let's close this door back up tight, right brother? Unless you are sure you want to open it? Really, like really for real sure with no backsies?"