WATCH: Yale historian explains the terrifying purpose of Trump supporters' angry chants

Trump supporters who attend his rallies regularly break out into angry chants ranging from "Build that wall" to "Lock her up" to "CNN sucks," among others.

Timothy Snyder, a Yale historian and the author of "The Road to Unfreedom: Russia, Europe and America," says that there is a direct line between these angry chants and the rituals that fascist dictators have used to build and maintain support among their citizens.

"This is going to be a tough one to hear and people aren't going to like it, but it's very hard to understand that, in fascism, we're not individual human beings who have thoughts and reflect before we speak," explains Snyder, in a video posted on Sen. Bernie Sanders' (I-VT) Twitter page. "The idea is that we are tribes."

The best way to maintain tribal solidarity, says Snyder, is to define the tribe's enemy that can be a focus of its members' hatred.

"The politics begins from deciding who the enemy is," he says. "So rather than being an individual, rather than thinking, what we're supposed to do is mark ourselves up into a tribe and define who the enemy is."

He also says that it's "no accident" that these chants appeal to certain elemental emotions, such as "the feeling that you need boundaries, the feeling of anxiety, the notion that others are different, and therefore threatening."

Watch the video below.