AN APPEARANCE at Pride has become a rite of passage for many politicians eyeing new offices. Maura Hennigan, a district councilor from Jamaica Plain, is running for an at-large seat on the Boston City Council this year. “I have a huge gay constituency in the district I represent now,” she said. “I’m running citywide, and people in the district know me, but I just wanted to let people in the rest of the city know how supportive I am and to thank them by being here.” Gubernatorial candidate Warren Tolman, who was the Democratic nominee for lieutenant governor in 1998, also showed up, and marched with his family. “I’m here to show my support for the gay community and commitment to equal rights, and I wanted to bring my children along so they can grow up learning tolerance and acceptance for everyone,” he said. “We had a good talk about it in the car.”

Brian Joyce of Milton looked a little lonely, marching with his wife and one supporter, but — one day before Max Kennedy unexpectedly dropped out of the Ninth Congressional District race — he was the only candidate for the seat who turned up. Preparation time — or propriety — could be a factor, since Moakley had been buried only the week before. It may also reflect the ideology of the district. Tracy observes that to run in the Eighth, “you have to be defined as a liberal Democrat, but it doesn’t seem as true for the Ninth,” which has large swaths of suburbia and two of Boston’s more conservative neighborhoods, West Roxbury and South Boston. But Joyce, for whom Saturday was his first Pride march, is going all-out for the gay vote. “I’m here to show my very strong support for the gay and lesbian community,” he said. “Frankly my biggest regret is I didn’t bring a placard, because I didn’t realize how many people were going to be here.”

For heterosexual officials in heavily gay districts — such as State Representative Byron Rushing of the South End, who has participated almost every year since 1982, and marched this year with the Episcopal Divinity School — it’s important to defuse potential challenges from gay candidates, and a regular presence in Pride is one way to do that. “When [openly gay Republican] Mike Duffy ran against Byron Rushing,” recalls Caucus co-chair Gary Daffin, “we supported Byron. You can’t abandon someone who’s delivered.” Gays are also a crucial part of the equation for anyone trying to build a progressive coalition. Arroyo — who considers gays a key part of his progressive base — was intent on getting his message out that “each individual has a right to have equality and respect.” Notes former city councilor Larry DiCara, “If Felix is to be a viable candidate, he has to do extraordinarily well in the gay community.”

But for straight pols, Pride is perhaps most useful as a means of transforming public perceptions: by marching, the elected official once viewed as parochial and conservative instantly morphs into a moderate with liberal street cred. And sometimes it’s not just the perception that changes; as straight pols build relationships with the gay community, their support for gay issues often grows. Notes Boston gay activist David Gearhart, “You see often, as people get a larger constituency, they become more open to the gay constituency.”

Take, for example, Mike Capuano, who was the mayor of Somerville before his 1998 election to Congress. The congressman, a scrappy Democrat who exudes a blue-collar sensibility despite his Dartmouth College degree, hadn’t distinguished himself on gay issues during his tenure as mayor, and during the congressional race many gays saw him as distinctly conservative. But he turned out to march as a candidate in 1998, and again as a congressman in 1999. Once in Washington, he learned fast. “The job has really opened my eyes to what’s going on in the rest of the country” with regard to discriminatory laws and practices, he says.

Capuano marched again this year, with one supporter — not an impressive contingent compared to the show of force put on by some pols (nearly 100 supporters marched with Cheryl Jacques, clad in matching pink-and-navy campaign T-shirts). Capuano wasn’t the most articulate defender of gay rights, either. He was participating in Pride, he said, “to show my support for AIDS research and equal rights, and all that sort of stuff.” But actions speak more eloquently than words. He’s co-sponsoring domestic-partnership legislation and a bill to allow partners of gays to become American citizens. “As far as I know, he’s been perfect on gay issues,” says Daffin.

Michael Flaherty — who hails from South Boston, the neighborhood famous for excluding a gay contingent from its annual St. Patrick’s Day parade — has similarly worked to build a reputation as a new generation of Southie politician. Though he’s participated in Pride events before, this year was his first time actually marching. He wanted to send the message that “we’re all God’s children” — and, it should be noted, he was the only pol I talked to all day who was savvy enough to use the phrase “gay, lesbian, bisexual, and transgender,” which is the gay community’s preferred designation nowadays.

Desire to escape the parochial label also informs this year’s mayoral race. Mayor Menino, the “Urban Mechanic” from Hyde Park, is famous for filling potholes and building playgrounds, but he’s also distinguished himself on gay issues. He’s invited gay youth to hold a prom in City Hall, he refuses to march in the Southie St. Patrick’s Day parade because it excludes gays, and he even turned down a request from the Cayman Islands’ consul to stage a festival on City Hall Plaza because the island’s government is hostile to gays. His director of campaign operations this year, Michael Kelley, is openly gay — as was Ann Maguire, his campaign manager during his first mayoral race, in 1993.

Similarly, Menino’s challenger for the mayoralty, Peggy Davis-Mullen, marched for the third time this past Saturday. She also has a record of strong support for the community, bucking her conservative South Boston base in 1996 by voting to extend domestic-partnership benefits to city employees. “I can tell you I’ve been a friend and advocate of the gay community not only during election time, but all the time,” she says.

Conservatives may never warm up to gay-pride marches, which still rankle the Catholic Church, along with a fair share of Boston-area constituents. Liberal politicians have been marching for a while now, accepting Pride as “equivalent to Columbus Day or any other civic-day parade,” in the words of former Alliance chair Dena Lebowitz. But more than ever, middle-of-the-road pols are now turning out. Notes Democratic political consultant Goldman, “Getting a Michael Capuano to march — people say, ‘He’s not a lefty liberal. If he can march, it’s not so crazy.’” Especially — as more and more pols are learning — if it gets you in good with 12 percent of Boston voters.

Dorie Clark can be reached at dclark[a]phx.com.