I don’t think the usual reason, he’ll sign whatever tax cuts and appoint whatever judges they want, is a reasonable explanation. Pence would do that for them as well as Trump, but without the Trump baggage.
I think the more likely explanation is that our conventional politicians have grown allergic to exercising power. I think it’s even too ambitious a goal to ascribe to conventional Rs that they actually want to pass tax cuts themselves. Too risky. Can’t do that without alienating some voter somewhere. Safer to get reactionary judges on the bench to exert any power to change public policy. Appoint judges who will declare that whatever progressive feature of the tax code they want to get rid of is unconstitutional. The only agenda the party could really get behind with enough unity to achieve the goal is getting judges in place to do their dirty work for them.
I don't think even a D Senate and House would be any closer to doing its duty and removing Trump than the Rs currently in charge. In fact, Trump would be even safer from removal if Ds had won control of House and Senate last election, because Ds are even more reluctant to “play hardball”, which is how doing their duty and removing a democratically elected president would be thought of in our power-allergic state.
What it would take to get Congress to impeach or use the 25th to remove Trump, would be huge D victories in 2018, giving us control of both chambers. But even then, the Ds would not do their duty unless they had made removal of Trump the issue on which they campaigned in that election. But that won’t happen because the party’s message instead of campaign these days, messaging being the strict and careful avoidance of saying exactly what you will do if given the power of the office you’re running for.
Our political non-system is a complicated non-system. No one can say with any certainty why it has produced any given result, such as Trump’s EC win last November. But let me add this theory of how that happened to the huge list already out there. Trump won because he’s not conventional. He doesn't message, he says what he thinks. His thinker thingy is off, so what he thinks is deranged. But what he says is, precisely because it's off, obviously not calculated to achieve an effect while avoiding saying what he thinks. He is therefore seen as the lone truth-teller in our politics by a big chunk of the electorate, despite the content that his demented mind spews having little discernible relation to reality. It takes knowledge of the content to see that someone's statements are at odds with reality, and for public policy issues, that knowledge is complicated and esoteric. You just need common sense to see when people are avoiding saying anything, as are all of our politicians except Trump. To anyone with common sense, politicians who may have an infinitely better grasp of the content of public policy — but don’t care or don’t dare just say what they think needs to be done — are obviously lying. Trump is only obviously lying or deranged to the much smaller group of people who have some grasp of public policy issues.
There are only two ways out of this situation in which the demented guy holds power because he is perceived as the only truth-teller, because he’s the only one not messaging. The way that inertia and entropy dictates (so of course it’s what we’re going to try first, as a default) is for all of us to at least pretend to be as demented as the crazy truth-teller, in order to seize power from him. It’s what we Ds have been doing since 1972 in the face of growing R depravity and insanity. The other option is for those of us who know what we’re talking about to stop messaging, to just say, and then do, what needs to be done. But you have to say it first, you have to get the party to all say it at once as its plan and intention if given power, because what needs to be done cannot be the deed of any one person, if we are to continue to have a representative democracy.
We’ve got to that place they reach at the end of Lear. It’s time to speak what we feel, not what we ought to say. Lear was king by accident of birth, and his dementia is thus largely symbolic and emblematic of what his kingdom had become after years of the people in power not speaking what they feel, but instead calculating what they ought to say. Trump is more than a symbol and emblem of our pathologies. He is our elected monarch right now because someone with dementia is the only person who can get into power in a system we have pushed so far into artifice and deception and insincerity that anyone who knows what he or she is talking about has to avoid at all costs letting on to that. Conventional politicians have aped dementia for so long to get elected that the actually demented guy doesn’t suffer in comparison on that count, while at least he is genuine, not faking his dementia.