There is now enough polling evidence to conclude that Bernie Sanders is surging, and he’s surging at exactly the right time. I’m writing this piece less than a week before the Iowa caucus, where he leads three of the last four polls. I’m writing two weeks from the New Hampshire primary, where he’s been up in each of the last six primary polls. And if he wins both states in consecutive weeks, watch out. As we know from past presidential primaries, victory creates its own momentum. Sanders may well be the Democratic nominee.

Most smart people accept this possibility. He almost won in 2016, after all. But could he win the general election? Key figures in the Democratic establishment have a singular message, “Don’t risk it!” Key figures in the Trump camp are practically cackling with glee at the prospect of taking on Bernie. “All the Democrats have to do is not be crazy,” they say, “and Bernie is crazy.” Writing in The Atlantic, David Frum made the case that “Bernie Can’t Win”—in part because Bernie is a gold mine for opposition researchers. When he goes from insurgent outsider to major party nominee, Frum says Bernie is in for a pummeling:

The members of the team around Sanders are experts in Democratic Party factional infighting. Few have dealt with people who do not play by the rules of the mainstream Democratic Party. They have always been the rule breakers, the people who got inside the other team’s decision cycle. They have been the Minute Men fighting the Redcoats, picking off the other side’s regulars from behind trees and fences. Now they are about to experience what happens when a militia faces off on an open field against a ruthless modern army with cluster bombs and napalm. They will be shredded and torched.

Consider me dubious. Make no mistake, I don’t think Bernie is the Democrats’ most formidable general election challenger, but I think he can win. And I don’t think it’s that hard at all to understand why.

Let’s start with the central organizing fact of modern American politics—negative polarization. The New York Times’s Thomas Edsall stated the problem well. Gathering a host of data from multiple sources, he declared, “Hostility to the opposition party and its candidates has now reached a level where loathing motivates voters more than loyalty.”

Let’s put it another way, every single factor that caused reluctant Republicans to hold their noses and vote for Trump will apply to reluctant Democrats. “Binary choice,” they’ll hear. “Judges,” they’ll declare. And, unlike 2016, when a host of people on both sides of the aisle thought there was no way that Hillary Clinton would lose to Donald Trump, not a single member of the Democratic coalition will be complacent. They’ll attack the election with fierce moral urgency. In other words, don’t hold your breath waiting for a “Never Bernie” movement in progressive media.

Next, when considering the effect of negative polarization, never forget that Team Blue is simply bigger than Team Red. Republicans have won exactly one popular vote since 1988, and they won that (in 2004) by a mere 2.4 points.

The difference is particularly staggering if you look at voting peaks. Donald Trump won 62,984,828 votes in 2016, more than any GOP candidate in history. In 2008—when America had a smaller population—Barack Obama won 69,498,516. Bernie Sanders is no Barack Obama, but the Democrats have a higher floor, and a higher ceiling.

Yes, I know all about the Electoral College, but to give you a sense of the fragility of Trump’s lead, just remember that two of his states—Wisconsin and Michigan—would be blue if Hillary had been able to generate Obama’s 2012 turnout in just two cities, Milwaukee and Detroit. Republicans have hope because of Trump’sElectoral College win, but it’s debatable whether they should have confidence. There’s no “red wall.” There is barely a red picket fence.

The bottom line for Democrats is simple: Turn out Team Blue, and they win.

What about all of that opposition research about Bernie? It’s real. Just today I saw a video on Twitter of a shirtless Bernie singing “This Land Is Your Land” in the Soviet Union during his honeymoon. He’s written strange things. He’s demonstrated an odd affinity for loathsome left-wing regimes.

But Bernie isn’t running against normal Republicans—men whose “scandals” include a long-distant DUI or placing a dog on the roof of his car. Trump could toss away his phone tomorrow and do his best Reagan impersonation from now until Election Day, and the leaked stories from his first three years will match or exceed anything Trump throws at Bernie. And we know he won’t toss away his phone. We know he won’t act like Reagan.

Yes, Trump’s behavior is “baked in,” but it’s baked in both directions, and a majority of Americans don’t like it, or him. America’s relatively few swing voters will be looking for an excuse to vote for Bernie.

Moreover, the atmospherics of the two campaigns will be profoundly different. Trump will run on dystopia. Bernie will run on utopia. Remember this campaign ad, from 2016?

Now imagine not just a theater full of young, hopeful faces. Imagine stadiums. Imagine that enthusiasm and sense of hope magnified by a mainstream media (especially online) that will march happily behind Bernie’s banner. Trump will call Bernie dangerous. He’ll mock Bernie. He’ll rage at Bernie. Trump’s supporters will claim that Bernie will “end America,” and Bernie’s people will respond—as they so often do—with simple messages. “How is health care dangerous?” “How is college dangerous?” “How is peace dangerous?”

Oh, and there’s the small matter that only two of the last 22 head-to-head polls show Sanders trailing Trump.

Moreover, we cold-hearted analysts and nerds always seem to underestimate the power of victory and hope. If Bernie wins the nomination, he would have triumphed over impossible odds and a small army of scoffers. Just like Trump. If Bernie wins, his core base voters will start to believe that their dreams can be a reality, and they’ll stand with him even if he shoots a man on Fifth Avenue.

I know there are effective tactical and strategic responses to each element of the Sanders campaign and the Sanders platform. I’ll say again—I agree that other Democrats have better odds of beating Trump. Bernie would alienate at least some of the suburban voters who voted Democratic in 1998.

While I believe that Sanders would frighten conservative voters in the same way that Barry Goldwater frightened liberals, I disagree with the idea that Sanders carries Goldwater’s downside risk.

America’s a profoundly different nation than it was in 1964, and we’ve reached a point in our national polarization when both parties can nominate previously unthinkable candidates and still enter the general election with a real chance for a win. Primary voters rule American politics, and the lesson many of them have learned from the last three presidential elections is clear—compromise loses. Devotion wins. And of all the Democratic candidates in the field, nobody inspires devotion quite like Bernie Sanders.

When election night ends this November, it’s entirely possible that the exuberant Republican joy of 2016 will have transformed into abject despair. The improbable presidency of Donald Trump may well have paved the road to the unthinkable presidency of Bernie Sanders. And we’ll have our hatred to blame.

Photograph of Bernie Sanders at a campaign rally in Queensbridge Park on October 19, 2019, in Queens, New York City by Bauzen/GC Images.