Read: How far have the Democrats moved to the left?

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. Senators Elizabeth Warren and Kamala Harris each initially embraced Sanders’s Medicare for All, but backed away when they started to see it as a political liability. Now Harris is out of the race, and Warren has fallen out of the top tier.

Other ideas may enjoy widespread approval, but face different hurdles. Warren has been asked tough questions about her proposal for a wealth tax. The idea is extremely popular, but many legal scholars believe her plan wouldn’t pass muster in court. Sanders, too, wants a wealth tax, and his is even bigger. It’s equally constitutionally dubious, but he hasn’t faced the same sort of doubts. Partly that’s because the press has been slow to take Sanders seriously as a candidate.

But that split in coverage probably also reflects what attracts voters to Sanders. Warren has grounded her appeal in wonkiness and know-how, making questions about the viability of specific plans make-or-break. Sanders’s appeal is more personal.

As the runner-up in the 2016 Democratic race, he entered the 2020 contest with strong name recognition, on a tier with only Biden. According to Morning Consult, he also has the highest favorability of all the Democratic contenders. Core to his personal appeal is authenticity. Politicians are famous for changing their views based on what is popular, a charge that’s especially potent against Biden. Sanders has been saying the same things, in largely the same fashion, for decades. Whatever you think of these ideas, they are sincerely held.