Michael Moore’s one-man show on Broadway is at times hilarious, at times tedious. While theater critics found “The Terms of My Surrender” greatly wanting, the liberal audiences seemed grateful for some comic resistance to the Donald Trump era.

Problem is, Moore is their problem. Or, at risk of inflicting a narcissistic injury on the lefty provocateur’s sense of centrality in great liberal causes, part of the problem. Had ticket buyers known his history of aiding and abetting the forces he purports to fight, they might have added Moore to their boycott lists.

They certainly would have choked at Moore’s opening complaint: “How . . . did this happen? The second time in the last 16 years we got the most votes!”

Ah, 16 years ago. That’s when Moore and other purifiers of the rigid left openly urged liberals to throw the election to George W. Bush. The race was so close that Republicans were sending checks to the campaign of left-wing spoiler Ralph Nader. It was in all the papers.

But Moore worked the Nader rallies with his rumpled-workingman shtick. “A vote for Gore is a vote for Bush,” he insanely bellowed. “If they both believe in the same thing, wouldn’t you want the original than the copy?”

Democrat Al Gore won the popular vote by a half-million but lost the Electoral College, as Nader siphoned off a few progressives in Florida.

Later in the show, Moore bitterly denounced Democrats who voted for “Bush’s war” and the liberal publications that endorsed it. Truth is, the claims that Saddam Hussein had weapons of mass destruction were more believable at the time than the contention that Gore was just like Bush.

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The lesson of 2000 had been forgotten by 2016, when Bernie Sanders and allies caricatured Hillary Clinton as a handmaiden of dark Wall Street forces. They condemned her as a toady of corporate America for having backed the Trans-Pacific Partnership. Actually, the TPP was a good deal for most American workers but an easy target for demagoguery. (Trump ditched TPP, and now most Democrats support it.)

Sanders was not a spoiler in the Nader sense. He vied for the Democratic nomination and eventually supported the Democratic candidate. But self-importance so clouded his judgment that he saw little danger in letting the “witch” bleed until almost the end.

Even after Clinton amassed 3.6 million more votes than he did, Sanders withheld his endorsement for weeks. At the Democratic convention, some Sanders ninnies booed Clinton’s name without serious reprimand by their leader. And a Sanders group put out a flyer reading, “Join us to hear why Hillary Clinton is more dangerous than Donald Trump.”

Trump picked up the talking points where Sanders left off. Clinton ran a flawed campaign, but when Sanders said after the election that she should have been able to put Trump away, you just wanted to . . .

So what should Democrats do? They should encourage states to hold primaries attracting a broad swath of voters rather than caucuses dominated by a few well-trained strategists. They should require Democratic candidates to be registered Democrats. And they should insist that candidates for president release their tax returns.

All the above Sanders opposed. He does get some grievance points for the party leaders’ favoritism toward Clinton. They should desist.

Meanwhile, Democratic leaders should stop indulging heretic hunters who can’t tell the difference between Gore and Bush, Clinton and Trump. Better that they leave the tent in a sulk than juggle blowtorches on the inside. As for problematic hangers-on like Moore, they are simply a burden. It’s time to label them as such.

Froma Harrop is a syndicated columnist.