Ridiculous though it may be, Nancy Pelosi apparently is serious about impeaching President Trump. This will have zero practical effect, of course, since he is leaving office in a week. It is just an expression of the insane hatred that motivates so much of what the Democratic Party does.
Impeachment after the fact has precedents. In medieval Europe, death did not make one safe from charges of heresy. An alleged heretic could be prosecuted and convicted posthumously, and if convicted, his remains would be exhumed and ceremonially burned at the stake. This is a pretty precise analogy to what the Democrats have in mind. Donald Trump was, after all, a heretic. He stood up for the American people.
If the Democrats do impeach Trump, the Republicans should return the favor when they re-take the House in 2022 (or whenever). They should retroactively impeach Barack Obama. Obama was far more guilty than Trump of inciting violence: “If they bring a knife to the fight, we bring a gun.” When did Trump ever say anything like that? He didn’t. And the violence that Obama helped to incite–the BLM/Antifa riots–have killed at least 30 people, dwarfing the total who died in last week’s Washington riot. So if the Democrats impeach Trump, the Republicans should respond by impeaching Obama.
UPDATE: Here’s a thought: someone who still has a Twitter account (mine has disappeared) should simply tweet Obama’s words–“If they bring a knife to the fight, we bring a gun”–and see whether the tweet is banned as an incitement to violence.