As an ideologue, Sanders faces challenges. Though he has modulated his tone since his earliest political excursions—more Franklin D. Roosevelt and less Rosa Luxemburg, as my colleague Franklin Foer pithily put it—Sanders’s politics, which he calls democratic socialism, are not yet all that popular. There is no question that the Democratic Party has moved left in recent years, and as I have reported, that shift is actually more pronounced among voters than it is among the party’s candidates, notwithstanding highly visible officeholders such as Representative Alexandria Ocasio-Cortez.

Overall, however, American views on socialism remain mixed to negative. Democrats, especially young ones, are growing more favorable toward socialism—a term that’s rather vague in most polls. But among Americans at large, a recent NBC News/Wall Street Journal poll found that a slight majority (53 percent) held a negative view of socialism, versus 19 percent whose views were positive. (Capitalism polls much better, 52 percent for and 18 percent against.) And in a second poll, 53 percent of respondents told Gallup they would not vote for a socialist for president.

Even within the Democratic Party, though, views of socialism as a concept may be very different from opinions on specific policies. Consider Medicare for All, Sanders’s signature proposal. People tend to like the idea when they’re simply asked about that name. Tell them it means they’ll lose their private insurance and they start to soften.