His father, who was also a California lawmaker, tried it when he was in office, too.

The most recent version of the legislation — which requires two-thirds approval from legislators before a constitutional amendment can be put to California voters — is on hold for now. But Mr. Mullin said he’s undeterred.

“We had this thing moving for most of 2019,” Mr. Mullin said. “We think we’ll be successful and potentially have it on the 2020 ballot.”

As teenagers take center stage in the global movements to stop climate change and curb gun violence in schools, the effort has never felt more urgent.

Ella Yitzhaki, a 17-year-old who lives in San Francisco, proudly identified as political; she said she’s been interested in the workings of our electoral processes since she was 10.

Ms. Yitzhaki said she was enraged by much of what she saw in 2016 — including the format of the debates and the candidates’ rhetoric. And she was very much looking forward to making an impact this time around.

“We are in one of the most exciting primary seasons ever,” she said. “We need to allow students and teenagers to have that full vote.”

Hannah Kim, a 17-year-old high school senior in Los Angeles, said that as a first-generation U.S. citizen, she’s taken the initiative to research candidates and develop her viewpoints. As a young woman of color, she said, she feels compelled to push back against the people who have told her “to get out of this country.”