The San Francisco teens have mustered a number of persuasive arguments why they should have just as much right to part the voting-booth curtains as their 18-year-old siblings. They pay sales and income tax. They drive and park in the city. They are affected by funding decisions, sometimes more than adults. And they can be tried as adults in court.

But perhaps most persuasive is the idea that granting 16-year-olds the vote could have a positive impact on civic engagement beyond their demographic.

“My parents don’t vote—they were not even registered—so growing up, I’ve never gotten the chance to freely express myself or voice my opinions,” says Anna He, 16, the Youth Commissioner for District 6, which encompasses both the single-room occupancy dwellings of the Tenderloin and the tech-industry palaces of South Beach.

Once He was appointed to the Youth Commission and began pushing the Vote16SF proposal, cracks appeared in the ice of her parents’ political indifference. Her mother has since registered to vote.

York calls this phenomenon “the trickle-up effect.”

“Some preliminary work has suggested that when young adults and children are considering local affairs, their parents will start doing it, too,” he says.

Then there’s the fact that 18 is a really inconvenient age to start voting.

“Last year I had a whole bunch of friends who [were] going off to college and I asked them, ‘Are you going to vote? How does that work?’ and they said, ‘I don't know. I’ll live on the opposite side of the country,’” York reports. For a lot of young people, the disruption of moving away to college pushes back their first vote, sometimes for years.

The hope—and there is some research to back this up—is that casting a first ballot at 16 or 17 will lead to a lifetime of voting and civic engagement.

If they succeed, Vote16SF’s champions will have struck a major blow for the fledgling youth suffrage movement. In the United States, so far only two small communities in Maryland, Takoma Park and Hyattsville, have lowered the voting age to 16. A number of states do allow 17-year-olds to vote in primaries if they’ll be 18 by the time of the general election.

After a good youth turnout in its referendum, Scotland lowered the voting age to 16 for all elections, but Britain’s parliament shot down a proposal to let teens vote in the planned referendum on whether to leave the European Union.

Whether they win or not, the proponents of teen suffrage in San Francisco are in for a valuable, and probably hard-won, lesson in policymaking. This spring, a team of four San Francisco supervisors (described by a conservative San Francisco columnist as “the left wing of the city’s left wing”) co-sponsored a measure to put the teen suffrage question in front of voters. But then Supervisor John Avalos put the measure on hold, saying it would be better to get it onto the 2016 ballot when the presidential election brings a higher turnout.