This kind of evolution would start with opposition to Democratic attempts to admit new states (and new senators), add extra justices to the Supreme Court or expand automatic voter registration and early voting. But Republicans could also mount a counteroffensive to lock in their current advantages — expanding voter-ID laws and making them stricter, pushing for House apportionment to exclude noncitizens, even trying to set up Electoral College-like systems for statehouse elections in states that might trend left.

You can see a dangerous cycle here, where the resilience of a counter-majoritarian Republican Party further delegitimizes the system in the eyes of Democrats, who become more radical in response, pushing us toward some stress point that’s far more serious than this month’s war over the Post Office.

I have spent much of the Trump era arguing that he is too feckless and incompetent, too much of a buck-passer and coward, to represent an authoritarian menace in his own right. But even if there are limits to how far the party will go with him — witness the swift disavowal of his election-postponement speculation — he has clearly habituated many of his supporters to a “caudillo” style, a politics of enmity, a sense that transferring power to Democrats is like letting suicide bombers seize the plane.

So it’s hardly fanciful to imagine a Republican successor who maintains the authoritarian style but drops the fecklessness. Put that kind of figure in charge of a party organized around holding power without majority support, pit it against a Democratic Party nurturing fantasies of an American “color revolution” — in which mass protests and even military intervention force out a right-wing government — and you could have a constitutional crisis sooner rather than later, and a Trumpian legacy that’s very dark indeed.