No definition of populism will fully describe all populists. That’s because populism is a “thin ideology” in that it “only speaks to a very small part of a political agenda,” according to Cas Mudde, a professor at the University of Georgia and the co-author of Populism: A Very Short Introduction. An ideology like fascism involves a holistic view of how politics, the economy, and society as a whole should be ordered. Populism doesn’t; it calls for kicking out the political establishment, but it doesn’t specify what should replace it. So it’s usually paired with “thicker” left- or right-wing ideologies like socialism or nationalism.

Populists are dividers, not uniters, Mudde told me. They split society into “two homogenous and antagonistic groups: the pure people on the one end and the corrupt elite on the other,” and say they’re guided by the “will of the people.” The United States is what political scientists call a “liberal democracy,” a system “based on pluralism—on the idea that you have different groups with different interests and values, which are all legitimate,” Mudde explained. Populists, in contrast, are not pluralist. They consider just one group—whatever they mean by “the people”—legitimate.

This conception of legitimacy stems from the fact that populists view their mission as “essentially moral,” Mudde noted. The “distinction between the elite and the people is not based on how much money you have or even what kind of position you have. It’s based on your values.”

Given their moral framing, populists conclude that they alone represent “the people.” They may not win 100 percent of the vote, but they lay claim to 100 percent of the support of good, hardworking folks who have been exploited by the establishment. They don’t assert that the neglected people who back them should be kept in mind by political leaders just like all other citizens; they claim that these neglected people are the only people that matter.

“[P]opulists only lose if ‘the silent majority’—shorthand for ‘the real people’—has not had a chance to speak, or worse, has been prevented from expressing itself,” explains Jan-Werner Müller, a professor at Princeton University and the author of What Is Populism? “Hence the frequent invocation of conspiracy theories by populists: something going on behind the scenes has to account for the fact that corrupt elites are still keeping the people down. … [I]f the people’s politician doesn’t win, there must be something wrong with the system.” ...