AT LAST SATURDAY’S Boston Pride march, Mayor Tom Menino was right behind the “dykes on bikes.” Pols from across the river, in Cambridge, marched alongside the contingents of rainbow-bedecked marching bands, gay scuba divers, and leather enthusiasts streaming through Back Bay and the South End. Boston City Council hopeful Felix Arroyo — wearing a Pride flag in the breast pocket of his suit — requested a spot next to the gay Brazilian contingent, where men in sequined outfits played the drums and danced. Just behind the candidate, his fundraising consultant, Rose Arruda, boogied down the boulevard, in a halo and silver angel wings.

In other words, it was ground zero in local politicians’ annual fight for the gay vote. The event, now in its 31st year, may be raucous fun, but the political stakes are high. A 1999 report by the National Gay and Lesbian Task Force Policy Institute says that in the 1996 and 1998 congressional elections, the gay, lesbian, and bisexual (GLB) vote accounted for nearly nine percent in the nation’s largest cities (those with more than half a million residents). The report goes on to observe that those numbers make the GLB vote as important as the nationwide Latino vote (about five percent) or Jewish vote (about three percent).

According to the policy institute’s Sean Cahill, the gay vote may be even bigger here. “Boston is a magnet city for gay and lesbian people, in that there’s a really great quality of life, and people are tolerant, so we’re probably even more than nine percent of the vote. We’re probably 12 percent,” he says. “Elected officials are just pragmatic and understand that in order to win the election, they don’t want to alienate 10 percent of the vote off the bat by ignoring the biggest gay celebration of the year.”

Jeremy Pittman, of the Lesbian, Gay, Bisexual, and Transgender Political Alliance of Massachusetts (known as “the Alliance”), agrees. “From a position of pure self-interest,” he says, “politicians are interested in showing their support for us, and hope we’ll show support for them.”

As support for gay rights becomes less controversial among the public, and as the community consolidates its political power, it’s not just liberals who participate anymore. Nowadays, Boston Pride is increasingly drawing mainstream pols who want the gay vote and are willing to come a-courting.

THERE WEREN’T any big-name politicians at Boston’s first Pride march, in 1970. In fact, there were hardly any marchers. Only 20 turned out — which was just as well, because the politically unsophisticated organizers didn’t realize they had to have a permit. The following year, recalls long-time lesbian activist Elaine Noble, she went to City Hall for the document and lied about the number she expected to attend — she said 75 — because the true figure, 35, would have looked too paltry.

Even worse, the clerk working at City Hall had been a student of hers at Emerson College. He was so rattled to see his former teacher requesting a permit for a gay event, Noble says, that he “mistakenly typed that the permit was being requested by Emerson College.” When college officials found out, they excoriated her for jeopardizing their tax-exempt status.

But the ranks of the parade slowly grew, and so did the political participation — starting at the fringes. Says Noble, “We had a lot of candidates from the Socialist Workers Party march in 1973.” A year later, Noble herself became the first out lesbian elected to state office, when she won a seat representing Boston’s Fenway and Back Bay neighborhoods in the Massachusetts House. She continued to march, and was joined by the then-closeted Barney Frank, who was also serving in the state legislature. “Politically it was seen as more risky — and it was,” recalls Frank, now a congressman from Newton. “Back then it was obviously more controversial.” Even other supportive politicians usually participated only by coming to speak at the tail end of the event. “Even after they were elected,” says Noble, “they were skittish, and wouldn’t march. I was the only one marching, but they’d show up to speak. They didn’t want to waste their time; they didn’t think we had enough clout.”

Frank believes that by the 1980s, it was significantly easier for pols to march. “By 1984,” he notes, “the Democratic national platform was supportive of gay rights.” Mayor Kevin White had appointed a gay liaison in the late 1970s, a practice continued by Mayor Ray Flynn, who himself showed up to speak at the rallies. Openly gay city councilor David Scondras became a major presence at the event. And then-governor Michael Dukakis participated in Pride events, though he later outraged community members with his support of a ban on gay foster parents. Still, fear of constituents’ wrath — often justified — kept many pols away. “We weren’t taken seriously; we were taken as a liability,” recalls Noble. Says former Boston city councilor Larry DiCara, “I remember marching in Pride parades in the early 1980s, and some of my supporters thought I was crazy.”

Those concerns worry some pols even today. “They don’t march for a lot of reasons,” says Democratic political consultant Michael Goldman. “Because they represent a conservative district, or they have a problem with the issue, or they don’t want to be seen condoning a different lifestyle.” But as the gay community became more politically organized, the benefits of visibly supporting gay rights began to outweigh the costs. At times, the community’s muscle was astonishing, generating thousands of letters to legislators during the 1980s urging passage of the state’s Gay and Lesbian Civil Rights Law. Gays amassed even more political capital with their support of Republican William Weld in the 1990 gubernatorial campaign, launching him to victory over the conservative Democrat John Silber.

Today, gay activists can still turn up the heat. State Representative Pat Jehlen of Somerville noted at last Saturday’s Somerville Pride flag-raising ceremony that she’s received more letters opposing an anti-gay-marriage bill than on “anything else I’ve ever had in the State House.” With their volunteer power and political energy, organizations like the Massachusetts Gay and Lesbian Political Caucus (known as “the Caucus”), the Alliance, and local groups like the Cambridge Lavender Alliance and OutSomerville became alluring friends for pols to cultivate.

“Every single year, it’s gotten more commonplace to see aspiring politicians in the parade,” says Arline Isaacson, co-chair of the Caucus. “When you compare 1980 to today, it’s night and day.” The 1998 march, in particular, drew what Sue Hyde of the Cambridge Lavender Alliance calls a “tidal wave” of pols as the race to succeed Joe Kennedy in the Eighth Congressional District heated up. Almost all 10 candidates marched, leaving gay voters with the knowledge that they had a plethora of supportive candidates to choose from — most notably Marjorie Clapprood, a straight but extremely gay-friendly talk-show host, and former Brighton state rep Susan Tracy, who had come out as a lesbian in the early stages of the campaign.

This year’s crop of pols was also impressive: it included a congressman (Mike Capuano, who won the Eighth in ’98); a congressional candidate (State Senator Brian Joyce, who hopes to succeed the late Joe Moakley in the Ninth); two gubernatorial candidates (Warren Tolman and Steve Grossman, who didn’t march but schmoozed before and after); the mayor of Boston; a slew of Boston city councilors (at-large councilors Peggy Davis-Mullen and Michael Flaherty, Jamaica Plain councilor Maura Hennigan, Allston-Brighton councilor Brian Honan, and Fenway councilor Mike Ross); a couple of at-large council candidates (Felix Arroyo and Rob Consalvo); and a district hopeful (Mark Juaire of Dorchester). Cambridge was represented by State Representatives Jarrett Barrios and Alice Wolf, city councilors Ken Reeves and Marjorie Decker, and city-council candidate Denise Simmons.

For openly gay pols like Barrios and State Representative Liz Malia of Jamaica Plain — and this year’s grand marshal, State Senator Cheryl Jacques of Needham, who is running for lieutenant governor — the march was a chance to build up volunteers and donors, not to mention emotional support. (Says Malia, “I wouldn’t miss this for the world.... It’s so amazing to see this number of people.”) For many other politicians, it’s the culmination of year-round support for gay and lesbian rights. But for every politician, the decision to march in Boston Pride is also a political calculation.