There’s a certain logic to all of this. Megan McArdle laid it out in an extremely prescient Facebook post just days after the 2016 election, writing that in the wake of losing the election to Trump, Democrats would undertake the kind of “autopsy” the GOP did in the wake of 2012, which posited Republicans should moderate on immigration to bring in Hispanic voters. Democratic leaders, she argued, would conclude that what they need to do is “back off the identity politics and embrace a more old-fashioned national greatness campaign mixed with pocketbook issues.”

But that would prove intolerable to the activist Democratic base, which is deeply invested in identity politics. Writes McArdle: “They will be incandescent. And they will put exactly the same sort of pressure on their politicians that the Tea Party put on Republicans. They will want to see their politicians blocking Trump even if it hurts the party overall, even if it means sacrificing bits of their legislative agenda that they could get done. They will demand costly symbolic acts that function as a repudiation of Trump, and a show of fealty to party interest groups.”

As we all know now, that’s exactly what has happened. From the Russia collusion hoax, to the Mueller probe, to the impeachment fiasco and all the routine acts of performative outrage along the way, the Democratic base has demanded all-out resistance to Trump, no matter if it alienates persuadable voters, no matter how far left it steers the party.