Here’s my fearless prediction for the 2020 presidential election: To borrow a Grateful Dead lyric, it’s bound to be a long, strange trip. No way it resembles a “normal” election year, whatever that would be.

Unremoved but very far from being exonerated, President Donald Trump isn’t going down without a wild spectacle. That much is sure.

Indeed, he may not go down at all.

Otherwise, the national experience of Trump’s presidency resembles that of a family dealing with a mentally ill relative. Nobody can possibly imagine what mad follies may come next. Over time, crazy people just wear everybody down. It’s easier sometimes to just let them have their way.

Might Trump push out Mike Pence and make daughter Ivanka his running mate? Bomb Tehran? Have Hunter and/or Joe Biden arrested?

Crazy, yes. Impossible? Not at all.

Meanwhile, Trump’s Democratic opponents, collectively speaking, inspire limited confidence. Moreover, as long as the U.S. economy surges, stimulated by runaway deficit spending of a kind Republicans pretend to abhor when Democrats are in power — Treasury Secretary Steven Mnuchin again predicts that Trump’s tax cuts will pay for themselves despite record trillion-dollar deficits — swing state voters could opt for the devil they know.

After all, Trump’s nothing if not entertaining. There appears to be nothing he can do, no lie so brazen it offends his cultlike supporters.

Thus, while there appears to be little chance of Trump winning a national majority, the GOP’s Electoral College advantage makes his re-election entirely possible.

So why am I seeing headlines like this one, in Newsweek? “Only 53% of Bernie Sanders Voters Will Definitely Support 2020 Democratic Nominee If He Doesn’t Win.” According to a recent Emerson College poll of 1,128 registered voters, just over half of Sanders’ supporters say they’ll definitely vote for any Democrat against Trump. (The equivalent number for Biden supporters is 87%; for Elizabeth Warren, 90%.)

This despite Bernie’s forthright vow at a recent Iowa debate that should any of his Democratic rivals win the nomination, “I will do everything in my power to make sure that they are elected in order to defeat the most dangerous president in the history of our country.”

Of course, that’s not how Bernie acted in 2016, when his support for Hillary Clinton was both grudging and late in coming. But then, like most Democrats, he probably thought there was no chance of Trump’s winning the presidency.

Sanders probably needs to double down on that vow if he really means it, because a significant proportion of his followers appears disinclined to accept certain basic facts about American politics. Specifically, as Ezra Klein recently explained in The New York Times: “[O]nly half of Democrats call themselves liberals — and for Democrats, that’s a historically high level.”

Much less radicals, or to use Bernie’s preferred term, people seeking a “revolution.” Many describe themselves as “moderate” or even “conservative,” by which they mostly mean in their cultural and lifestyle orientation.

Securing the Democratic nomination therefore requires, Klein explains, “winning liberal whites in New Hampshire and traditionalist blacks in South Carolina. It means talking to Irish Catholics in Boston and atheists in San Francisco. It means inspiring liberals without arousing the fears of moderates.”

To say nothing of winning the presidency. To put it another way, there just aren’t a whole lot of revolutionaries in Pennsylvania, Michigan, Wisconsin or Minnesota — states whose electoral votes could decide the November election. Bernie-style leftists predicted disaster during the 2018 congressional season; instead, mostly moderate Democrats took over the House.

So it’s distressing to read in The Washington Post about Sanders activists resorting to Russian-style Facebook smears against Sen. Warren. “Already, the pro-Sanders crusade has spawned groups calling for protests at the party’s national convention in July should Sanders not emerge as the nominee. #BernieOrVest is their rallying cry, echoing the Yellow Vest demonstrations that have roiled France.”

Yes, because Milwaukee, where the Democratic convention will be held, is exactly like Paris.

Now me, I disliked a lot about the ’60s the first time around. Historian Rick Perlstein’s book “Nixonland” brilliantly depicts how the excesses of self-dramatizing “radicals” back then — Bernie Sanders among them — led to a right-wing backlash that’s still very much with us.

Or as onetime ’60s leftist John B. Judis put it in recent essay, “[t]he ’60s left’s rebellion increasingly took a religious rather than a political form. It consisted of establishing one’s moral credibility and superiority in the face of evil.”

Did you know that Bernie once wrote crackpot columns blaming cervical cancer on women not having orgasms? That he joined a political party taking Iran’s side during the 1979-80 hostage crisis? That he honeymooned in the Soviet Union? There’s video.

Should he secure the Democratic nomination, you will.

It’s that or the Yellow Vests. Your call.

(Arkansas Times columnist Gene Lyons is a National Magazine Award winner and co-author of “The Hunting of the President” (St. Martin’s Press, 2000). You can email Lyons at eugenelyons2@yahoo.com.)