These critiques, unsurprisingly, inspired all sorts of conspiracy theories and wild accusations. I was told by two celebrities that their inability to register as Democrats and vote for Mr. Sanders on the day of New York’s primary showed them “the dark underside of American politics.” Mrs. Clinton has “gamed the nominating process,” and her election will leave “a national majority of citizens in open rebellion,” wrote a retired professor on Alice Walker’s official website. An online, “instant documentary” charged the Democratic Party — and by extension, Mrs. Clinton — with outright fraud at the polls in California. Once Mr. Sanders’s defeat became inescapable, some of his most die-hard believers began to argue that a Trump presidency might even be preferable to having Mrs. Clinton in the White House.

“In a way she is more dangerous,” Susan Sarandon insisted in June, warning that under a President Clinton, “We’ll be in Iran in two seconds.”

But other Sanders diehards are quite prepared to “bring the jubilee” and accept a transformative, Trump victory.

“I’d rather see the empire burn under to the ground under Trump, opening up at least the possibility of radical change, than cruise on autopilot under Clinton,” the journalist Christopher Ketcham wrote in The Daily Beast, adding that “the left-contrarian, anti-Hillary, pro-Trump arsonist crowd is larger and wider spread than the cubicled creatures in the Clinton campaign have accounted for.” Mr. Ketcham urged Mr. Sanders to run on the Green Party ticket, and thereby toss the election to Donald Trump. This could, he conceded, “usher in the end of the democracy, the death of the republic, the rise of the hard totalitarian state.” But what the heck? After all, “we are already living in what Princeton political scientist Sheldon Wolin calls a soft or inverted totalitarian system.”