SACRAMENTO — Jennifer Siebel Newsom, wife of California Gov. Gavin Newsom, endorsed Massachusetts Sen. Elizabeth Warren for president on Friday.

In a video posted to social media, Siebel Newsom, a documentary filmmaker who has adopted the gender-neutral title of “first partner” and established a public agenda around issues like pay equity, asked voters to make Warren the first woman president.

“Sen. Elizabeth Warren is the brightest person in the room and she actually cares about each and every one of you, especially our women, our children and our nation’s most vulnerable,” Siebel Newsom said. “She knows you can’t live a good life in an unjust society, and she will revive the American dream for all of you who call this country home.”

California is the biggest delegate prize on the presidential primary calendar and one of 14 states that will vote on Super Tuesday next week. While Vermont Sen. Bernie Sanders has pulled away from the rest of the field in California, according to recent polls, Warren sits in second place — just on the cusp of the 15% support she would need to earn delegates.

I am so proud to announce my endorsement of Elizabeth Warren for President!



Now more than ever, women need a champion in the White House & we need a fighter to defeat Donald Trump.



So on #SuperTuesday, please join me in voting for Warren & together let's make history! pic.twitter.com/fxzI2E4Ln0 — Jennifer Siebel Newsom (@JenSiebelNewsom) February 28, 2020

“Please think about your wives, your mothers, your sisters and your daughters,” Siebel Newsom said. “Vote your conscience, not what the pundits and the billionaires are telling you to do. Because Sen. Elizabeth Warren is electable.”

Warren, in a statement, praised Siebel Newsom for using her films and her office to advance women’s representation.

“Women must have a seat at the tables of power, whether that’s in government, business or anywhere in society,” she said.

Gavin Newsom was an early endorser of his longtime political ally Sen. Kamala Harris but has not backed another candidate since she dropped out of the race in December. He has declined to answer questions about who he is supporting, though he said Wednesday that the debates have been helpful as he comes to a decision.

“I can only say this: My voice mail’s full,” Newsom said.

Alexei Koseff is a San Francisco Chronicle staff writer. Email: alexei.koseff@sfchronicle.com Twitter: @akoseff