The consultant who ran Supervisor Sandra Lee Fewer’s 2016 campaign is facing a state ethics complaint, alleging that he violated a law barring candidates from communicating with independent expenditure committees.

Progressive strategist Jim Stearns worked as a consultant for Fewer while producing slate mailers for the Affordable Housing Alliance, the complaint said. But the mailers that Stearns’ group sent out didn’t endorse a slate of candidates or ballot measures — they merely attacked Fewer’s opponent, Marjan Philhour.

“In this case, Jim Stearns was brazenly coordinating with himself,” said the complaint filed by pro-density housing activist and startup founder Vincent Woo.

It went on to accuse Stearns of using $280,000 from the American Beverage Association — colloquially known as “Big Soda” — to fund the anti-Philhour mailers, disguising the source of the money.

Stearns said it’s routine for political consultants in San Francisco to work for candidates and also put together slate mailers and that it’s the responsibility of the organization behind the mailers — in this case, the Affordable Housing Alliance — to follow the rules.

Stearns accused Woo of making the complaint in order to harrass and intimidate someone who falls on the opposite end of the housing debate. Pro-density activists — many of whom descibe themselves as “YIMBYs” —are known for using legal complaints to move their political agenda forward.

The state’s Fair Political Practices Commission bans slate mailer organizations from simultaneously functioning as campaign committees to support or oppose a candidate, officer, or ballot measure.

As for the “Big Soda” contribution, California’s Political Reform Act mandates that election campaigns “fully and truthfully” disclose all their funding sources, said commission spokesman Jay Wierenga.

— Rachel Swan

Email: cityinsider@sfchronicle.com, rswan@sfchronicle.com Twitter: @sfcityinsider @rachelswan