But the 2020 primaries have discredited Mr. Sanders’s strategy, Eric Levitz writes at New York magazine. He notes that while Mr. Sanders has made impressive gains with Hispanic voters, the promised surge in youth turnout has not materialized: In many states, including Mr. Sanders’s home state, Vermont, young voters’ share of the electorate fell from 2016. And while total Democratic turnout did increase significantly in most states, that increase tended to help Mr. Biden.

“The left isn’t going to maximize its ideological influence over Democratic voters, or its power within the party, by pretending that it commands an enormous army of nonvoters who are ready to storm the Democratic castle as soon as Sanders gives the signal,” Mr. Levitz writes. To get what it wants, “the left must first win with the electorate it has, not the one it wishes it did.”

[Related: “The Sanders Surge That Wasn’t”]

Mr. Biden’s delegate lead is small at the moment, but it could be hard to overcome, writes The Times’s Nate Cohn. Although Mr. Sanders needs to defeat Mr. Biden by only three points in the remaining primaries to overtake him, Mr. Sanders will not have the advantage he enjoyed on Super Tuesday of early votes cast before Mr. Biden’s South Carolina victory, a showing that prompted other candidates to drop out. The remaining states are also projected to be less favorable to Mr. Sanders than, say, California was. “A three-point deficit is not a daunting handicap, certainly not when Mr. Biden was polling 20 points lower just a few days ago. But the Super Tuesday results do not augur well for Mr. Sanders’s odds of pulling it off,” Mr. Cohn writes.

Many people believe that Mr. Sanders is losing because voters see Mr. Biden as more electable. While Mr. Sanders is well liked among Democrats and his platform popular, his candidacy demands a leap that many voters fear others are not willing to make, as the Times columnist Frank Bruni has noted.