The most revealing moment of last night’s Democratic presidential debate came near the end, when CNN moderator Anderson Cooper asked the candidates to “name the one thing—the one way that your administration would not be a third term of President Obama.” Bernie Sanders replied that, unlike Obama, he would “transform America ... through a political revolution.” Hillary Clinton answered that, unlike Obama, she’s a woman.

The responses reminded me of a distinction Chris Hayes makes in his excellent book, Twilight of the Elites, between “institutionalists,” who want to make existing institutions function better and “insurrectionists,” who want to tear them down and start again.

Sanders is an insurrectionist. That’s why, asked about following the most transformational liberal president in a half-century, he didn’t say that America is moving in the right direction but has further to go. He said America needs a “political revolution.” He also said that, “America’s campaign finance system is corrupt.”

Hillary never talks that way. She acknowledges problems but she rarely indicts America’s core economic and political institutions. Consider the two candidates’ answers on financial regulation. Sanders said that, “Wall Street, where fraud is a business model, helped to destroy this economy and the lives of millions of people.” Thus, “we have got to break up” the banks. Hillary, by contrast, said that “Dodd-Frank was a good start, and I think that we have to implement it ... We have to save the Consumer Financial Protection board.” Sanders, in other words, attacked the system; Hillary explained how it could be improved.

On race and crime, it was much the same. Sanders called America’s criminal justice system “broken” and riddled with “institutional racism.” Hillary called for “following the recommendations of the commissioner that President Obama empanelled on policing. There is an agenda there that we need to be following up on.”

In explaining her vote for the Patriot Act, Hillary said the legislation created a valuable “process” but the Bush administration had begun “to chip away at that process” and thus, “the balance of civil liberties, privacy, and security” needed to be restored. Sanders didn’t talk about balancing competing values or getting the process right. Anderson Cooper asked, “Would you shut down the NSA surveillance program?” and Sanders replied, “Absolutely. Of course.”

It was like that all night. Sanders called for replacing capitalism with democratic socialism. Clinton called for “rein[ing] in the excesses of capitalism so that it doesn’t run amok.” Sanders boasted that he had opposed a bank bailout even after America’s top economic officials warned that not passing one might bring “a complete meltdown.” Hillary essentially embraced the label of “insider,” declaring that she knows “what it takes to get things done.”

Hayes’ distinction isn’t only a useful guide to what the candidates said in the debate. It’s a useful guide to their competing strengths and weaknesses. Sanders’s insurrectionism is crucial to his political appeal. Progressives don’t just love him because his policy proposals are more left wing than Hillary’s. They love the fact that he calls America’s political and economic system corrupt, and that he refuses to play by that corrupt system’s rules: for instance, by raising money via a super PAC. That’s why being a “socialist” doesn’t hurt Sanders among many liberals. For many, “socialism” is just another way of saying you want to tear down the existing order and build something better in its place.

But if Sanders’s insurrectionism is key to his success, it may also put a ceiling on it. As angry as many liberals are about economic inequality, the Democratic Party is today in a far less insurrectionist mood than the GOP. Republican presidential candidates routinely bash John Boehner, to wild applause. If a Democratic candidate attacked Nancy Pelosi, liberals would think he or she were nuts. And Democrats still really like Barack Obama.

That’s why, during the debate, Hillary hugged Obama so close. She played to the fact that while Democrats think some big things in America are fundamentally wrong, they also believe their leaders are trying to make things better. Under Obama, in fact, they believe that things have gotten better. One reason Hillary couldn’t beat Obama in 2008 was that after George W. Bush, she didn’t seem to be offering big enough change. But now that she’s running to succeed a president most Democrats like, her inside-the-system, incremental approach enjoys more appeal.

Bernie Sanders, like Donald Trump, can only win if a plurality of primary voters want to turn their country, and their party, upside down. With her performance last night, Hillary Clinton reminded Democrats—in a way Jeb Bush has still not reminded Republicans—why that might not be necessary after all.