The claim is abroad in the land that the Democrats should not impeach Trump because doing so will energize his base.
Anyone who is part of his base at this point will never abandon him. We should not trim the nation’s sails to suit them. They like the person who is far and away the worse president in the history of the republic, a man who harms our fellow citizens and the republic as a whole daily. They like a man who said that most Mexicans are rapists and murderers. Who proposed, then enacted, a ban on all Muslims entering the country. Who mocked a disabled reporter. Who routinely makes up demeaning nicknames for his opponents.
Let us recall that Trump lost the popular vote in 2016.
Had he been a candidate in 2018, he would have lost by an even larger margin. The 2018 turnout was historically huge and decisively returned the Democrats to control of the House, in what one can only read as a loud repudiation of Trump. Democrats only failed to regain the Senate because they faced a very bad map. There is no good reason to think that anyone will be much happier with Trump in 2020 than they were in 2018.
Impeaching him, even if the Senate fails to remove him, will only further tarnish his reputation and likely goad him into even more stupid behavior. The tweets alone will be worth the price. The investigation leading to impeachment will entail a painstaking review of all of his crimes, with testimony from anyone who has relevant knowledge and is willing to appear. The court battles over compliance with subpoenas will make him look petty and offer multiple opportunities to ask what he is hiding if he has done nothing wrong.
Nixon went to the Supreme Court to resist surrendering recordings of his Oval Office conversations presumably because he knew they contained damning information.
Finally, and most importantly, Democrats should ignore Trump’s base and impeach because doing so is more likely to energize the Democratic base.
Forgetting about your own base because you’re worrying about the other guy’s base is really stupid.