Trump exposed the chasm between the GOP establishment and Republican voters. Bernie Sanders is about to do the same for Democrats.

After Wednesday night’s disastrous debate performance by former New York mayor Mike Bloomberg and a flurry of recent polls showing Sen. Bernie Sanders surging ahead of the pack, it’s safe to say there’s a very strong likelihood Sanders will be the Democratic nominee.

How did this happen? The simplest answer is that what happened to the Republicans in 2016 is now happening to the Democrats. I don’t just mean that Sanders is now poised to win plurality after plurality in a primary field that will likely remain crowded through March, fracturing the non-Sanders vote between three or possibly four other candidates. That’s more or less what Donald Trump pulled off four years ago amid a crowded GOP field, and that’s part of what’s happening now.

Also, of course, Democratic primary rules and delegate apportionment are more complicated than they are in the Republican Party, so there’s a scenario in which Sanders could be denied the nomination at a contested convention even if he wins a plurality of delegates in the primaries.

But from a broader perspective, the emergence of Sanders as the Democratic frontrunner mirrors the rise of Trump and the crackup of the Republican Party in 2016, and for many of the same reasons. In both cases, a significant swath of each party’s voter base rejected the party establishment after years of being pandered to or ignored altogether.

Populism cuts both ways, right and left, and the impending takeover of the Democratic Party by a left-wing populist should have been anticipated by party leaders four years ago—and maybe it would have been, if they hadn’t been busy gloating over the GOP’s apparent misfortune of being taken over by Trump.

Sanders Is Doing to Democrats What Trump Did to the GOP

But Trump’s triumph was a necessary corrective to a party that had lost its way. When Trump cinched the nomination in 2016, it was the end of the Republican Party as we knew it. Gone was the mild-mannered GOP of Mitt Romney, Paul Ryan, and John Boehner. Gone were the empty platitudes, repeated ad nauseum for decades, about comprehensive immigration reform and defunding Planned Parenthood. Gone was the slavish devotion to global free trade deals regardless of the toll it took on American workers. Gone, too, was the subtle deference toward the liberal media that belied the Republican establishment’s ambivalence about the issues rank-and-file Republicans really cared about.

Trump swept all of that away. Before he went to war with Democrats and the media, his candidacy was an all-out assault on the Republican establishment, which had drifted so far from its base that GOP leaders didn’t take him seriously until it was too late. They couldn’t see what he saw: Republican voters—and not a few independents and moderate Democrats—were tired of being ignored by their leaders, whom they had grown to despise. Trump was able to topple the edifice of the GOP because he saw it was rotten underneath.

Now, Sanders is poised to do the same to the Democratic Party. The media is aware of this, but only vaguely, tending to frame Sanders’s rise as a contest between a radically leftist base and a more moderate Democratic electorate at large. That’s one reason the press has so quickly glommed on to the candidacy of Bloomberg, treating him as a viable contender for the nomination and a real rival to Sanders.

But the truth is that rank-and-file Democrats are far more comfortable with Sanders than the Democratic establishment is. You don’t generally see headlines touting this, but Sanders enjoys support even among primary voters whose first choice is one of his rivals. A Quinnipiac poll earlier this month found that among supporters of Elizabeth Warren, Pete Buttigieg, and Joe Biden, the vast majority—98, 97, and 92 percent, respectively—say they would vote for Sanders against Trump. The same poll found that Sanders’s net favorability was second only to Warren’s, and a Monmouth University poll recently found his net favorability among Democrats nationally was 71 percent, six points higher than Warren and 40 points higher than Bloomberg.

Democratic Party bigwigs can mutter amongst themselves about how ordinary Democrats won’t rally around Sanders, but so far the polls, at least, tell a different tale.

The Democratic Establishment Faces A Reckoning

There’s a certain logic to all of this. Megan McArdle laid it out in an extremely prescient Facebook post just days after the 2016 election, writing that in the wake of losing the election to Trump, Democrats would undertake the kind of “autopsy” the GOP did in the wake of 2012, which posited Republicans should moderate on immigration to bring in Hispanic voters. Democratic leaders, she argued, would conclude that what they need to do is “back off the identity politics and embrace a more old-fashioned national greatness campaign mixed with pocketbook issues.”

But that would prove intolerable to the activist Democratic base, which is deeply invested in identity politics. Writes McArdle: “They will be incandescent. And they will put exactly the same sort of pressure on their politicians that the Tea Party put on Republicans. They will want to see their politicians blocking Trump even if it hurts the party overall, even if it means sacrificing bits of their legislative agenda that they could get done. They will demand costly symbolic acts that function as a repudiation of Trump, and a show of fealty to party interest groups.”

As we all know now, that’s exactly what has happened. From the Russia collusion hoax, to the Mueller probe, to the impeachment fiasco and all the routine acts of performative outrage along the way, the Democratic base has demanded all-out resistance to Trump, no matter if it alienates persuadable voters, no matter how far left it steers the party.

Just as the Tea Party didn’t care how much they were called crazy racists and kooks by the media and the political establishment, left-wing Democrats don’t care about being called socialists or mocked for supporting the Green New Deal, Medicare for All, free college, and so on. Being the party out of power in a hyper-partisan political era means these Democratic voters are going to demand all the things they’ve long wanted.

They are unrestrained because they are out of power—for now. And although they desperately want to beat Trump in November, for now their target is the Democratic Party itself.