But she also said she was interested in Ms. Warren and wanted to hear her speak.
Jiego Lim, an 18-year-old student at the University of Nevada, Reno, who was volunteering at Mr. Sanders’s event there, said he supported Mr. Sanders but was also intrigued by Mayor Pete Buttigieg and Senator Kamala Harris. “I feel like we need a fresh new face in politics,” he said. “Bernie comes off aggressive to me sometimes.”
Others were less equivocal.
“He’s America’s dad,” offered Gabriel Olier, 19, a student in Reno. “I love Bernie.”
That affection for Mr. Sanders is reflected in some more tangible metrics. His campaign said it had so far raised over $1 million from people under the age of 25, a relatively small figure compared to his overall haul but one that nevertheless points to his continued strength with young voters.
[Here’s the latest data on who’s leading the race to be the Democratic nominee.]
And in most polls, Mr. Sanders still maintains a strong lead among young voters: A recent NBC/Wall Street Journal survey showed that a third of voters under 35 supported him.
Yet at the same time, a quarter of these respondents said they supported Ms. Warren, suggesting Mr. Sanders no longer has the same hold on the group he had in 2016.
Any candidate relying on the support of younger voters faces an undeniable challenge: Younger voters tend not to vote in high numbers compared with other groups. In the 2016 election, for instance, only 11 percent of voters under 30 participated in the Iowa caucuses, representing just 15 percent of the total, according to an estimate from the Center for Information and Research on Civic Learning and Engagement at Tufts University.
But the high turnout among young voters during the 2018 midterm elections has given some experts hope that the 2020 election will be different. That strong showing has provided organizers with a larger pool to identify and target potential presidential voters. Issues, including climate change, criminal justice, health care and gun control, are also motivating young voters to act.