Bernie Sanders is the Left’s Donald Trump.

Bear with me here. There is a lot they don’t have in common, including where they stand in their respective party’s polls—though Sanders’s slow creep into a distant second is likely to be more sustainable. Still, they have both managed to disrupt their respective nomination races, and they’ve done that because they both have a similar appeal: They’ve tapped into anti-establishment passions with rhetoric that is a kind of wish-fulfillment fantasy for some voters. “He has the guts to say what others won’t” could be the slogan for either of them.

I don’t want to gloss over the content of that gut-driven bluntness. In Trump’s case, just because he’s saying what others won’t doesn’t mean what he’s saying is true. And it’s fair to point out that Trump’s lowest-common-denominator xenophobia is a sugar high kind populism: it’s cheap and easily reproduced but difficult to sustain. Sanders, on the other hand, offers a chewier and less visceral version of “us-versus-them”: Discussions about income inequality and financial regulatory policy don’t create the same kind of direct line to voters’ emotions that Trump’s talk of rapists and thieves travels on.

The media is covering them in a similar fashion, too, though that’s mainly a function of how the political media cover campaigns in general. The story is the process, not the messages or ideas. “Analysis” consists of asking, “What this will do the race?” and not, “What does it mean for voters?” Granted, only one of the candidates in question has ideas to cover. Indeed, Sanders’s reliance on a few big ideas—not personality, not easy outrage—is one of the reasons coverage of his rise has an element of arch bemusement. Note The New York Times: “Somehow, Bernie Sanders, the 73-year-old senator from Vermont, has emerged as a king of social media.” Somehow!

Trump coverage, of course, is more straightforwardly mocking (I highly recommend the Trump Chrome extension). While everyone wonders what Trump’s rise might do to the GOP race, no one is wondering how it is he got as far as he did. Just ask any of the other, “more serious” candidates, whose reluctance to criticize Trump proves that his only real divergence from the Republican mainstream is stylistic, not substantive.

On the other hand, there are real policy differences between Sanders and the Democratic leadership—that’s why he wasn’t a Democrat until recently, after all. Moderate Democrats have been denouncing Sanders with a vigor conspicuously absent from the intraparty Trump conversation: Missouri Senator Claire McCaskill complained, “I very rarely read in any coverage of Bernie that he’s a socialist” and declared him “too liberal” to be president.

Put it another way: When Democratic base voters flock to Sanders, they are expressing dissatisfaction what current Democratic policies. When Republican base voters flock to Trump, they are expressing dissatisfaction with Republican rhetoric.

But I said I was going to talk about what they had in common, and that’s easy enough here: Whether it’s rhetorically or policy-wise, Trump and Sanders supporters are asking their parties to move away from the center—or, perhaps more clearly stated, away from each other.

Indeed, there are those on both sides who long for a Trump-Sanders match-up. It would, on some level, be a battle of caricatures—as defined by the opposing side. And what about the Democrats who would love to see Trump get the nomination? And Republicans who’d like to see Sanders? They envision that contest as referendum more than an election, a chance to finally and fatally eject the other side from the political spectrum. As Glenn Beck put it recently: “I think we need to just cut to the chase and have a real libertarian/conservative go up against Elizabeth Warren or avowed socialist Bernie Sanders. This country could finally make up its mind based on two honest and completely different visions of the future of this country.”

A nation born of revolution is given to absolutes, of course. (“Give me liberty or give me death,” no middle ground, etc.) But the Founders never thought we’d be using those words against each other. Beck and others frame the prospect of two extremists as a contest of “visions” but both sides are actually colorblind: Everything is black and white. One side is totally wrong; one side is totally right. This zero-sum mentality and vengeful nihilism threaten to turn government into just another WWE show, a cage match of ideologies.

Left unspoken in these hyperbolic hypotheticals is what happens if the other guy’s caricature wins. That 50-50 chance of total validation is just too blinding, I guess. But what happens if their own caricature wins, more often than not, is just as vague. It’s standard practice to snigger when asking a supporter of a fringe candidate (though neither Trump nor Sanders are really fringe) what will happen were their dream president actually to sit down in the Oval Office. The objectively ridiculous proposition of a President Sanders or a President Trump actually trying to govern is supposed to destabilize the fantasy.

But the attraction of a Sanders or Trump presidency for true believers isn’t the opportunity to govern all of us, but the chance to punish the rest of us.