IN THE six months since the late Joe Moakley announced that he had leukemia, the question of who Menino wants to replace him has turned from a no-brainer into a guessing game. When Kennedy partisans first pushed the candidacy of Max Kennedy, a son of Robert F. Kennedy, most political observers believed that Menino would support him solidly. After all, why would Menino risk angering Boston’s powerful patron in the Senate, Ted Kennedy, by dissing his nephew?

When Kennedy abandoned his race before it officially began, however, things became somewhat more complicated. Soon after Kennedy dropped out, the Boston Herald’s David Guarino wrote that Menino seemed to be backing Lynch: " Menino appears willing to set aside his sometimes-rocky relationship with Lynch to help him beat back suburbanites to keep the seat in Boston’s hands. " As evidence, the Herald reported that Menino’s chief strategist, Ed Jesser, was helping Lynch. Other Menino allies — especially those from Dorchester and South Boston, such as Michael Flaherty — are backing him as well. But in July, Jacques entered the race. She’s a favorite of some progressives — especially gay, lesbian, and pro-choice voters — and as such has enjoyed at least some tacit support from the mayor.

Jacques, for example, was warmly received at Menino’s annual house picnic on July 12. The manager for Menino’s first mayoral campaign, Ann Maguire, escorted the Needham state senator around to meet supporters for part of the time. The rest of the time, she was conducted around by the mayor’s wife, Angela. Lynch arrived later — once Jacques had already gone. Sources close to the mayor downplay Jacques’s treatment as merely respectful. Still, the incident ruffled feathers within the Lynch team. To them, Menino was a " trimmer " — in other words, a two-timer, one who tries to make it look as if he favors each side.

That’s not the only help coming to Jacques from the mayor’s camp. John Cullinane and Gerard Doherty, both key Menino allies, are serving as the co-chairs of her campaign. Finally, Laurie Sherman, a policy adviser to the mayor, helped introduce Jacques at a recent house party held for the candidate in Jamaica Plain. Sherman notes, however, that she was present in her capacity as a neighborhood activist with the Bourne Area Gays and Lesbians. (Joyce, meanwhile, has the support of David Breen, an attorney in the city’s legal office, as well as several other City Hall employees in their private capacities.)

Menino’s decision not to get fully behind Lynch may result from numerous pragmatic calculations, including the need to balance the desires of his various constituencies. It also may reflect the mayor’s reluctance to see the rise of a powerful official with a South Boston address. A Lynch victory would mean a new political power source in the city. It’s true that Menino always had to deal with Moakley. But because Moakley was so much older and so much part of the established order of Boston’s political universe, Menino ceded territory to him — especially on issues relating to the federal-city relationship, such as federal land on Boston’s waterfront.

Menino has seemed very comfortable dealing with political figures whose bases lie outside of Boston, such as Congressman Michael Capuano of Somerville and, most prominently, Governor Jane Swift. Nobody knows, however, how Menino will like dealing with a new, young de facto mayor of South Boston. Remember, although Menino is popular citywide, South Boston in some ways remains enemy territory. Menino is still at war with Jimmy Kelly, who, along with Lynch and Jack Hart, compelled the mayor to sign the now-infamous deal that shifted 51 percent of developers’ linkage money to South Boston at the expense of the rest of the city. Once public outcry over the deal reached critical mass, Menino backed out of the plan. Kelly angrily filed suit, seeking to hold Menino personally liable for damages. (Lynch decided not to join the suit.) Remember also that Menino refuses to march in South Boston’s St. Patrick’s Day parade on the grounds that it bars gays and lesbians. Lynch, on the other hand, has said that he would participate even if he had a broken leg.

Part of what’s at work here, obviously, is Menino’s effort to please two masters — South Boston and city progressives. Menino needs to keep Lynch’s South Boston and Dorchester partisans from turning on him in an election year. Yet even as Menino seems to encourage — or acquiesce to — some level of support for Lynch among his ranks, he’s not yet going all the way. He needs to provide cover for the progressives within his ranks who want to support Jacques. As the first Italian mayor of Boston and the first non-Irish mayor in almost a century, Menino has gone out of his way to assemble a diverse coalition heavily weighted with gay supporters, progressives, and ethnic constituencies. (In April, for instance, Menino was the only Boston politician to appear at the state of Israel’s anniversary celebration or at Henry Louis Gates’s announcement of the Encarta Africana, a massive compendium of African and African-America history. Menino also has supported domestic-partnership legislation since serving as a city councilor.) Some progressive supporters may not approve if Menino endorses Lynch, who is anti-choice and, until very recently, opposed domestic-partnership legislation. In a move that irked progressives, Lynch invited State Representative John Rogers of Norwood, the sponsor of the state version of the Defense of Marriage Act that would ban gay marriages, to introduce him at his campaign kickoff.

" I think that progressives only have one place to go if they’re Menino people, and I think that’s with Jacques, " says Mary Breslauer, a gay activist and Jacques supporter. " I think that’s where some of his supporters are. "