Former Tri-Valley Assemblymember Catharine Baker has decided against running for the Alameda County Board of Supervisors, according to a source with knowledge of her decision.

Baker had been seriously considering a campaign for the open District 1 seat that includes Dublin, Livermore, Sunol, and most of Fremont. Last May, Supervisor Scott Haggerty announced that he would not seek re-election in 2020.

Without Baker, the potential March primary contest could become even more wide open than expected. Many had projected Baker as a strong candidate for the seat, if not, the early front-runner.

Polling in the race done sometime last month showed Baker topping a list of candidates that included, among others, state Sen. Bob Wieckowski, and Haggerty’s chief of staff Shawn Wilson. She did not, however, gain a majority needed to avoid a November run-off.

Although county contests are non-partisan, there may have been some worry about Baker’s registration as a Republican in expected high-turnout elections next year. Many believe Baker’s surprising upset in last year’s November election was due more to the taint of President Trump’s Republican Party brand in the East Bay than any missteps made by Baker. Her opponent, Democrat Rebecca Bauer-Kahan lost the June primary but authored a riveting come-from-behind victory in November to turn the seat blue for the first time in four years.

Baker’s possible candidacy for supervisor was already causing alarm among Alameda County Democrats, who had been burned twice by Baker’s two wins for the assembly in 2014 and 2016.

An open seat on the Alameda County Board of Supervisors is the rarest of birds in the East Bay. It’s also a position with tremendous power, no term limits, and receives little public attention to its day-to-day activities.

When Haggerty announced he would not seek re-election to his District 1 seat last May it triggered an immediate reaction. Wieckowski gave up a run for Congress to announce his candidacy for county supervisor, joining Fremont Councilmemeber Vinnie Bacon, who last January joined the race hoping to challenge Haggerty.

But in the weeks since Haggerty’s surprising announcement, what is expected to be a high-stakes race for supervisors appeared to hit a lull in excitement and a dearth of candidates jumping into the race. A number of East Bay political insiders said earlier this month that the calm before the storm could be attributed to uncertainty about whether Baker would run for supervisor. “They’re all waiting to see what Baker does,” said the source.

Baker’s possible candidacy for supervisor was already causing alarm among Alameda County Democrats, who had been burned twice by Baker’s two wins for the assembly in 2014 and 2016. Among the county’s deep blue landscape, Baker’s was the Republican Party’s lone star in the region. Rumors that Baker had left the Republican Party, apparently unfounded, have been floating among political insiders for weeks.

At least four other candidates are actively pursuing potential runs for county supervisor. They include Sue Chan, a former Fremont councilmember and current trustee on the Ohlone Community College District board; Dublin Mayor David Haubert and Dublin Councilmember Melissa Hernandez. Another curious name has emerged recently: Jacob Swalwell, an Alameda County deputy sheriff and brother of Rep. Eric Swalwell.

The totality of candidates interested in running for county supervisor would amount to an interesting March 2020 primary race. But those prognosticating the race believe the presence of duplicate candidates in Fremont and Dublin will eventually lead several to forego campaigns.

Bacon’s campaign already has a big head start on the competition. His campaign has been canvassing the Fremont portion of the district for months and is beginning to turn its sights on the Tri-Valley. He believes his fight over the years against developers in Fremont plays well to voters in Dublin and Livermore. Chan, also from Fremont, is popular in Fremont, but like Bacon, virtually unknown in the Tri-Valley.

The inverse goes for Haubert and Hernandez, two Dublin officials with zero name-recognition in Fremont, and both may have difficulty drawing support in that area of the district. But with Baker out, Haubert, a former Republican, could absorb some of her support, if he joins the race.