Former Rep. Katie Porter has endorsed state Sen. Scott Wiener in the contest for San Francisco's seat in Congress, adding a well-known Democratic name to his side about four weeks before the Nov. 3 election, KQED reported Wednesday.

Wiener is running against San Francisco Supervisor Connie Chan, a fellow Democrat, to replace Rep. Nancy Pelosi. The former House speaker is retiring after nearly four decades representing the city.

Why Porter says she's backing him

Porter, a consumer protection lawyer and law professor who represented an Orange County district from 2019 to 2025 and ran for governor earlier this year, pointed to Wiener's work in Sacramento on housing, health care costs and public transit. In her statement she called him someone who would be "a fighter for San Francisco families in Congress," and framed the race as a chance to send representatives who will stand up to President Trump and his allies on health care and living costs.

Wiener said in a statement that he was honored by the endorsement and repeated his core pitch: build far more housing to bring rents and mortgages down, protect affordable health care and invest in transit.

A tighter race than the primary suggested

Wiener finished first in the June top-two primary with more than 40% of the vote, while Chan took just under 30%, narrowly edging out progressive Saikat Chakrabarti for the second slot, according to CalMatters. KQED reported that Chan has gained ground since then. A September poll from Tavern Research showed Wiener ahead by 11 points, with a margin of error of 5.2 points.

Chan won a major boost in May when Pelosi endorsed her as her successor. KQED said she has also been endorsed by many labor unions and by former Sen. Barbara Boxer and former Rep. Jackie Speier, and CalMatters noted support from the California Labor Federation and SEIU California. Wiener has raised more money and has the endorsement of the San Francisco Chronicle's editorial board, as well as labor activist Dolores Huerta.

The campaign has been sharp. Chan has hammered Wiener over his ties to the tech and AI industries, while Wiener has accused her of blocking housing projects during a citywide affordability crunch. At their second debate, NBC Bay Area reported, the two clashed over AI regulation and policing but agreed on opposing U.S. military funding for Israel.

The candidates have two more debates scheduled, on Oct. 10 and Oct. 13, according to NBC Bay Area. Ballots are already arriving in voters' mailboxes.