As he runs for the 2020 nomination, Sen. Bernie Sanders (I-VT), a self-proclaimed democratic socialist, is going to have to define what that means in terms that don’t scare Americans.

Sanders was confronted with American wariness toward socialism during a CNN town hall Monday night, when one student told him that her family escaped from Soviet Russia in 1979, “fleeing from the same socialist policies you seem eager to put in this country.”

Sanders immediately clarified: He does not support authoritarian communism.

“Is it your assumption that I believed in authoritarian communism that was in the Soviet Union? I haven’t, and I opposed it,” Sanders said. “I happen to believe that in the United States, there is something fundamentally wrong when we have three families owning more wealth than the bottom half of American society.”

To be sure, Americans have a vastly different perception of socialism today than they did in the 1940s. In October 2018, Gallup found that more Americans understood socialism as some form of equality (23 percent) than government control of business and the economy (17 percent). Fifty-seven percent of Democrats held a positive view of socialism; only 16 percent of Republican voters viewed socialism favorably, Gallup found.

That said, a democratic socialist leading among candidates in the Democratic presidential primary is certainly new for the United States, and something Republicans are already using in attack ads.

Here’s how Sanders explained democratic socialism: