ST. PETERSBURG — With three weeks until the mayoral primary, challengers Kathleen Ford and Rick Kriseman took every opportunity Tuesday to paint Mayor Bill Foster as a pandering leader who flip-flops on major issues.During a Tampa Bay Times/Bay News 9 forum at the Palladium Theater, the pair criticized Foster's handling of the Pier, his stadium negotiations with the Tampa Bay Rays, his failure to develop Midtown and his lack of focus on neighborhoods.Kriseman, 51, struck first when asked to grade senior city administrators. "I would not give him an A," Kriseman said of Foster.Ford, 56, faulted Foster for not preventing Sweetbay Supermarket from closing this year in Midtown's Tangerine Plaza. "That is a real shame because I know how hard past administrations worked," Ford said.The hourlong forum's testiest exchange came when Kriseman and Ford were asked whether they, like Foster, would have fired Goliath Davis in 2011. Foster fired the former police chief and deputy mayor when Davis skipped the funerals for two police officers killed in the line of duty.The firing caused anger in the African-American community, where Davis is considered a respected leader. In May, Davis all but endorsed Ford, declaring her a viable candidate to lead the city.Foster, 50, said he had to fire Davis because they had "a significant difference of opinion."Kriseman dodged the question, saying he wasn't going "to question the hiring and firing decisions of the mayor."When pressed further by Times political editor and moderator Adam C. Smith, Kriseman said his management style "isn't to call somebody out in public. It's to have that conversation behind closed doors."Ford criticized the firing, saying she didn't "like the idea that some disc jockey called for the firing of a city employee and the mayor followed his orders."She also said she respected whatever reasons Davis had for not attending the funerals but stopped short of saying his firing was wrong. "I don't know all the facts . . . I don't like the way it was handled," she said.The attacks on Foster, who is leading in several recent polls, continued when the candidates discussed Foster's disclosure Monday that he is considering allowing the Rays to examine new stadium sites in Hillsborough County. For three years, Foster repeatedly has said the team is legally obligated to play at Tropicana Field through 2027."A new day, a new position," Ford said.Foster fired back: "It's not a change in position, it's really a difference of an objective."He said his goals are to protect taxpayers' $150 million investment and to keep the team in the region beyond 2027.Kriseman didn't buy that answer."On this issue, Mr. Foster had as many positions as (Rays utility man) Ben Zobrist. This is an important issue. It's not a game. It's a serious issue that involves the city."Near the end of the debate, candidates were allowed to ask one question of another.Both Foster and Ford targeted Kriseman, which could signal they both view him as a threat since he has climbed in recent polls and leads in fundraising.For her question, Ford went back to when Foster and Kriseman served together on City Council.She asked Kriseman what he and Foster learned from an incident years ago involving a Krispy Kreme calendar featuring obese women that was circulated around City Council chambers. The incident forced council members to attend one-on-one lectures on appropriate workplace behavior. "When you think about the issues you have facing us here in the city, my answer to that is it's really disappointing that is the question you ask," Kriseman responded.Foster chimed in: "We probably learned not to print another Krispy Kreme calendar."The mayor then took aim at Kriseman's tenure in the Florida House. Foster called Kriseman ineffective and said he passed no legislation in Tallahassee. He then asked Kriseman if he planned to bring partisan politics to the city."I'm the only candidate sitting up here tonight who has been endorsed by Republicans and Democrats on the County Commission," Kriseman responded.Kriseman then asked Foster how he could be trusted to manage budgets after his idea to fill a $9 million deficit was to charge residents a separate fee for fire service.Foster said he cut taxes in his first two years in office, and noted that the City Council rejected his fire fee.Mark Puente can be reached at [email protected] or (727) 893-8459.