Bernie Sanders’s message has resonated with the Latino electorate, particularly young voters. In both Iowa and New Hampshire, he won big among Latinos, and he is projected to do the same in Nevada this Saturday. But whether that support will transfer to a general election if “Tío Bernie” (Uncle Bernie), as he is known, manages to clinch the nomination is the big question.

The Latino youth Mr. Sanders is rallying haven’t been reliable voters. Though he’s favored by Latinos nationally, as new Washington Post-ABC News and Univision polls show, reports of his success haven’t accounted for voters for whom socialism is something to fear.

Mr. Sanders, aware that such a label might hurt his chances, has deflected conversations about his socialism, claiming they’re just efforts to redbait him. In 1981, as the newly elected mayor of Burlington, Vt., he said he had learned to stay away from calling himself a socialist, because he didn’t want to spend “half my life explaining that I did not believe in the Soviet Union or in concentration camps.” He embraced other terms instead, including radical, independent and democratic socialist.

While he may harbor unease about the label, his actions have said otherwise. In the summer of 1985, the mayor traveled to Nicaragua’s capital, Managua, for a commemoration of the sixth anniversary of the Sandinista revolution. While there, he praised the Sandinistas for fighting for women’s rights and economic justice. In a 1986 speech at the University of Vermont, he claimed to be “very excited when Fidel Castro made the revolution in Cuba,” because it seemed “right and appropriate that poor people were rising up against rather ugly rich people.”