Michael Kruse published a great essay in Politico yesterday, describing how Trump uses humor to make his extreme views and misbehavior more palatable to his audience. Trump has been described many times as more an entertainer than a politician, and it can't be denied that he has the beats and timing of an accomplished comedian. As Kruse's article points out, his rallies often have more the feel of an off-color stand-up routine than a stump speech. And as the piece goes on to observe, Trump is not unique in this regard. It's a tactic that has been deployed by other demagogues before him.
The strategy has also proved remarkably effective. On paper, after all, Trump's alleged crimes are horrifying (he has conspired to subvert a federal election; he has compromised the nation's security by willfully retaining classified documents, etc.). No less appalling are Trump's openly-avowed plans for the future: his commitment to building new detention camps, his promise of retribution against his political opponents, his pledge to carry out a mass deportation campaign that would rip apart communities. But by making a punchline of it all, it just... doesn't seem real.