Supervisor Eric Mar has an idea that stands in stark contrast to the national discussion about deporting immigrants who don’t have legal status — he wants to let noncitizens vote in local school board elections.

On Tuesday, Mar proposed a charter amendment at the Board of Supervisors’ weekly meeting for the November ballot that would allow the noncitizen parents, legal guardians or caregivers of students 18 and younger who are enrolled in San Francisco public schools to vote in local school board elections, whether they have a green card or a visa or are living in the country without documentation.

The proposal resurrects two previous ballot measures. In 2004, voters narrowly rejected the same proposal by then-Supervisor Matt Gonzalez with 49 percent in favor and 51 percent opposed. An even larger margin of voters rejected it in 2010, with 46 percent in favor and 54 percent opposed. Assemblyman David Chiu proposed that measure when he was a supervisor.

The political context now is different, Mar said, pointing to a backlash to Republican presidential nominee’s Donald Trump’s anti-immigrant rhetoric. Trump has called for a ban on Muslims entering the country and, more recently, claimed that a federal judge overseeing a lawsuit against Trump University couldn’t be impartial because of his Mexican heritage. He has also vowed to build a wall on the U.S.-Mexico border and deport about 11 million immigrants without legal status.

“In the previous campaigns, it was a different climate,” Mar said. “With Donald Trump’s racist and anti-immigrant sentiments, there is a reaction from many of us who are disgusted by those politics. I think that’s going to ensure there is strong Latino turnout as well as other immigrant turnout.”

Legally defensible

Legal scholars said it is unclear whether such a measure would pass legal muster. That it has been on the ballot in previous years means the city attorney’s office believes the proposal is legally defensible because that office vets ballot measures proposed by supervisors.

There is nothing in the U.S. Constitution that prevents undocumented immigrants from voting, said Erwin Chemerinsky, law school dean at UC Irvine. The 14th Amendment says no person should be denied equal protection of the laws. The 15th Amendment prevents the government from denying a citizen the right to vote based on his race.

While voting rights have traditionally only been extended to citizens, Chemersinky said, “if the government wants to give voting to a larger group of people like noncitizens it can do so if it wants to” — at least under the U.S. Constitution.

But David Carrillo, director of the California Constitution Center at UC Berkeley School of Law, said the measure probably violates the state Constitution.

“The California Constitution limits the franchise to citizens,” Carrillo said in an email. “And the Legislature (which controls voter qualifications for statewide elections) has by statute limited voting to citizens. So even if it passes, this measure’s prospects in the courts are dubious.”

Done in other cities

While San Francisco would be the first California city to extend voting rights to noncitizens, it has been tried elsewhere in the United States. Seven jurisdictions have extended voting rights to noncitizens, said Ron Hayduk, a political science professor at Queens College of the City University of New York.

Six of them are in Maryland — all allow noncitizens the right to vote in local elections. The seventh municipality is Chicago, which allows noncitizens to vote for local school councils, a quasi-management body at each public school.

In 2013, a majority of New York City Council members voted to extend voting rights in local elections to noncitizens, but were stopped by then-City Council Speaker Christine Quinn and then-Mayor Michael Bloomberg.

“The idea of early voting is it builds civic education, expands political participation and helps incorporate immigrants,” Hayduk said. “Opponents say there is already a pathway to vote, which is to become a citizen.”

Mar’s measure needs six votes at the Board of Supervisors to get on the November ballot. If it makes it, it will join another charter amendment that seeks to extend the right to vote in local elections to 16- and 17-year-olds.

Emily Green is a San Francisco Chronicle staff writer. Email: egreen@sfchronicle.com

Twitter: emilytgreen