Thorne announced his candidacy last month and plans to kick off his campaign at a fundraising breakfast Oct. 6 at the Alameda County Fairgrounds.
Both Thorne and Cook-Kallio were elected to their second four-year terms of office last November so will be seeking the mayor's post from so-called "safe" seats, meaning that even if they lose their bid for mayor, they will continue serving out the remaining two years of their council terms.
Cook-Kallio said she was announcing her candidacy reluctantly because she believes campaigns for municipal office should start closer to Election Day, not 14 months ahead of time.
"But the fact is that many supporters have been calling me to see if I'm a candidate after hearing that Councilman Thorne already is campaigning," she said. "So I've filed the necessary paperwork to show that, yes, I intend to run for mayor, and those who want to contribute to this effort can do so."
"I'll have an official campaign launch sometime in early 2012," she added.
Now the city's vice mayor, Cook-Kallio, said she has a major focus on issues such as state-mandated housing requirements, climate control initiatives and pension reform and does not want partisan politics to get in the way of a unified council approach to addressing these issues.
"The problem with deciding issues when a political campaign is going on is that no matter how hard you try, constituents think you're on the political pulpit when you talk about them," Cook-Kallio said.
Cook-Kallio, who lives in Pleasanton's Jensen tract across from Amador Valley High School, teaches civics, government and American history at Irvington High School in Fremont. She was first elected to the City Council in 2006, and then again last November, receiving 12,009 votes, or 28.3% of those cast in a four-candidate race for two seats. Thorne also won in that contest, receiving 14,201 votes, or 33.56% of the votes cast.