There are two related comments in this thread, from Patrick II and Addicted, that I think are worth highlighting:
I hate the argument that prosecuting Trump would be unprecedented. Having a gangster president flouting every law he comes in contact with as he attempts to destroy democratic order in the United States is also unprecedented. So you do what you must.
Not prosecuting Trump would also be unprecedented. It would be the first time that a US President blatantly broke the law and boasted about it in public and wasn’t prosecuted. It would be the first time in US history an outgoing President attempted an illegal coup and was not prosecuted.
Since Trump’s actions are unprecedented, the fact that prosecuting him would be unprecedented doesn’t actually tell us anything about how to proceed.
One of the central fallacies of the alt-centrist argument for giving Trump a pass even if he’s guilty will be familiar to fans of North American team sports. The NFL, NBA, and NBA are all difficult sports to officiate because of the paradoxical truth that the games would be unwatchable both if you called the rulebook to the letter and if you refuse to enforce the rules. Officiating therefore involves a tricky balance of discretionary norms. Sometimes, though, for high-leverage moments (especially in playoff games) — the NHL is the worst offender, although you hear it in other sports as well — there’s a common argument that refs should generally not call penalties because it would mean the refs were “deciding the game.” But of course this is silly, because refusing to call penalties that materially impact the game and would be called at other times is also “deciding the game.” Acts of omission impact the game just like acts of commission.
But at least a game is just a game. Refusing to consider the risks of omission and inaction — to adequately weight the downside risk of giving Trump an exemption no matter what he’s done – is incompatible with democracy. The idea that the law can’t be enforced against authoritarians who threaten violence is not new in American history. Exactly the same logic was used to justify ending Reconstruction, not enforcing Section 2 of the 14th Amendment, not enforcing Brown v. Board, not prosecuting lynchers, etc. etc. It is a position that is not compatible either with the rule of law or equal citizenship.