She became the sixth candidate for the District 4 seat that's up for grabs since Supervisor Rose Jacobs Gibson terms out this year. The district includes Menlo Park, Redwood City, East Palo Alto, and unincorporated North Fair Oaks and Oak Knoll.
Ms. Keith said that seats open up about every 12 years, since a supervisor can serve three four-year terms, meaning that it's a very long wait before the opportunity comes around again.
"A lot of people were asking me and encouraging me, so I thought about it and decided to go ahead," she said.
She was elected to the Menlo Park City Council in 2010 and was appointed mayor by the council this year. The mayor serves as chairman of the council, but has one vote just like the other council members.
She drew parallels between the issues facing the council — balancing the budget, transit, job growth, and economic development — and those challenging the county. "I think that translates very well."
Ms. Keith, a criminal defense attorney, has also served on the city's planning and housing commissions, along with several county panels on women's issues.
She sounded excited about returning to the campaign trail. "I think it's going to be really great." As for endorsements, Ms. Keith declined to announce any at this time.
That enthusiasm will be needed, as no fewer than six candidates are now running for the seat.
The field to date includes East Palo Alto councilmen Carlos Romero and David Woods, Redwood City Planning Commissioner Ernie Schmidt, Redwood City school board member Shelly Masur, and county education board trustee and Menlo Park resident Guillermo "Memo" Morantes.
If any one of the candidates gets more than 50 percent of the vote during the June 5 primary, the election is over. Barring that, there will be a runoff election in November, making for a lengthy countywide campaign season.
According to City Clerk Margaret Roberts, if Ms. Keith wins, the council could choose to appoint a member of the public within 30 days of her leaving office, or call a special election to fill the vacancy.