I wonder that too, but to be honest I’m a lot less confident than many that impeachment will happen in the first place. Gerald Ford described the problem pretty neatly forty years ago: “an impeachable offense is whatever a majority of the House of Representatives considers it to be at a given moment in history.” That’s where the process starts, and the House has an even greater Republican majority than the Senate (and House Republicans tend to be even less moderate than the senators, who are already voting along party lines for Trump’s cabinet nominees). As long as they get what they want without TOO much threat to establishment Republican power, I suspect it’s to their advantage to keep him around as a loud, highly visible, highly unpopular scapegoat for the worst of traditional Republican policies (“What? That wasn’t OUR fault, that was TRUMP’S fault”), as opposed to impeaching him and putting Pence in his place.
My real fear isn’t some sort of violent takeover in which elections are called off and Trump declares himself dictator for life (though the fact that that’s even a remote possibility on the radar is…insane). My real fear is that he does such damage to democratic institutions – and those damages become so normalized – that we go the way of the Roman Republic, which endured in name for YEARS after becoming an empire where real power effectively rested with one man. Or, y’know, the way of Putin’s Russia, which technically still has a representative government. If you feel like googling, Yascha Mounk studies this sort of thing and has a lot of smart (and depressing) things to say about the rise of illiberal democracies that preserve the forms of representative government while still being authoritarian in practice. To my way of thinking that’s a lot more plausible in 21st century America; even most of the hardcore Trump supporters like to THINK of themselves as believers in liberty and democracy and the Constitution. They’d get cold feet if he went full fascist and dissolved the government on them right away. At least I hope they would.