Don’t do what James Comey did
By 
John Ganz points out that one of the many problems with eleven-dimensional-political-chess arguments for not prosecuting Trump is that FBI/DOJ officials have no particular ability to see how their actions will impact the political landscape going forward, and indeed it was galaxy-brained political maneuvering by the FBI that stuck us with Trump in the first place:
These sorts of prevarications and what ifs have governed the way the political class and bureaucrats in this country have dealt with Trump from the beginning of his political emergence. James Comey bungled everything with all his efforts to appear unbiased and unpolitical, and ended up actually breaking protocol to keep up his charade of personal purity. Barack Obama was very careful and circumspect about how to talk about and deal with Trump in public, and he got criticized and blamed for the “Russiagate Hoax” anyway. Media commentators constantly create all these scenarios where any sort of aggressive stance towards Trump actually helps him. He’s got everyone twisted up in knots.
The thing about Trump is that he will say anything and do anything, and he will also try to get his followers to do anything. He essentially tried to overthrow the government of the United States. He’s a criminal on many levels. But we’ve convinced ourselves that if even if he’s not legitimate, we have to pretend he’s legitimate to placate his supporters. This is because Republicans, on top of all their other structural advantages, have performed an ideological trick on the entire country where they always an have extra little bit of Americanness: even when in the minority, they have a special something that makes it wrong to cross them. They are the “real Americans,” after all. It’s really an amazing feat, the political version of a small animal that has evolved to puff itself to appear intimidating. Republicans love to say, “What about the millions of people who voted for Trump? Are you just gonna ignore them?” Well, what about the millions of people who voted against him—twice. The will of the public here is pretty clear: “No to this guy.” But the press and even the opposing party constantly plays along with Republican bullshit. It’s part of the unspoken code of American politics that most conventional pundits reinforce. (Not for nothing, no one ever is like, “Well, what about Democrats? What will they think of all this?” The attitude there is always, “Shut up, libs. Crybabies. Snowflakes.”)
It’s time to stop fucking around. All of the savvy political wisdom of the preceding years got us here: with a half-lunatic trying to shake down the country to call off his followers. Trump doesn’t care about precedents: as soon as he’s able, he will use whatever tool he’s able to use against his opponents. This is why his supporters like him. They openly say so. The first time around, he didn’t really know how to wield the power of the state or the most violent core of his supporters, but most likely he will will learn. The Federal oath of office begins, “I do solemnly swear that I will support and defend the Constitution of the United States against all enemies, foreign and domestic.” If that means anybody in the history of the country, that must mean Trump. He cannot be allowed to hide behind his supporters or try to use them to manipulate the U.S. government. Is it possible that this will lead to bad outcomes? Sure, anything is possible. But treating Trump like he’s got special powers has lead us here.
The idea that Trump should get a heckler’s veto over law enforcement because he has a cult following is not attractive normatively, and nor have strategic decisions resulting from this assumption panned out at all.
The other issue here is that nobody actually knows what the political impact of prosecuting Trump as opposed to not prosecuting Trump will be. It’s ridiculous to simultaneously keep pointing out that prosecuting Trump would be unprecedented, and then make super-confident predictions about what will happen if he’s prosecuted. It’s all just speculation with no empirical basis by definition! The obvious answer is just to prosecute Trump if an investigation reveals that he has committed crimes anther person would be charged with and forget the third-rate Machiavellian bullshit that has consistently failed in response to Trump anyway.