Otherwise, the presumptive Democratic front-runner communicates a sense of moral and ideological certitude — unrelentingly sustained for decades — that seems to thrill his followers but terrifies me. Other candidates have changed their views on one thing or another over the years, albeit with varying degrees of sincerity: Joe Biden on the war in Iraq; Mike Bloomberg on stop-and-frisk; Elizabeth Warren on super PACs.

Not Bernie! The young man who joined the Young People’s Socialist League as a student at the University of Chicago in the early 1960s on the hoary notion that “capital” should be in the hands of workers, not capitalists, is now the old man who rails compulsively against “the billionaire class” and wants to nationalize the health insurance industry. The guy who was angry about the downfall of Salvador Allende’s Marxist regime in Chile in 1973 is still angry about it today.

He isn’t entirely letting go of Fidel’s achievements, either, even if it risks Florida’s 29 electoral votes. Yes, literacy in Cuba (largely for purposes of indoctrination) is high, and Sanders thinks he has a moral obligation to affirm this.

This isn’t to say that everything Sanders ever thought as a young man — and still thinks today — is wrong. At Chicago he helped force the university to end racial segregation in its private housing. He made the definitive case, in the pages of the college newspaper, for the right of students to have sex. He joined Martin Luther King Jr.’s March on Washington for Jobs and Freedom in 1963.

These are things of which the senator can be proud. Other things, not so much.

He was affiliated with the Trotskyite Socialist Workers Party when it was shilling for the Khomeini regime during the Iran hostage crisis. He shilled for the Ortega regime in Nicaragua in the 1980s, while denouncing skeptical journalists as “worms.” In 1985, as mayor of Burlington, Vt., he made the case for bread lines: “Sometimes American journalists talk about how bad a country is because people are lining up for food,” he said. “That is a good thing! In other countries, people don’t line up for food. The rich get the food and the poor starve to death.”