The least vulnerable of the four is probably Stephen M. Saland, a patrician-looking lawyer whose Poughkeepsie district sits about a two-hour drive north of New York City. A Capitol fixture since 1980 and a conscientious legislative technician, Saland negotiated with Cuomo the details of a shrewd compromise that assured religious organizations that they would not be compelled to participate in gay marriages, giving a bit of shelter to lawmakers worried about religious blowback. Saland agonized over this issue with his gay-marriage-supporting wife, but one acquaintance said his decision seemed to grow out of his immersion in the legislative language. He refused to talk for this article because of an old grudge against The Times over what an aide described as “an out-of-context quote.”

Roy J. McDonald, who represents former mill towns like Troy and Mechanicville, didn’t see much percentage in reminiscing about his vote, either. He literally backpedaled as I interviewed him in the Senate lobby. “I did what I thought was right,” he told me. The voters “understand that,” but now they want to talk about jobs and foreclosures, not marriage. “I can’t dwell on this stuff.” McDonald is a Vietnam veteran and former steelworker. Though he is now a banker, he retains a bluff manner, but with a compassionate streak when it comes to those born different. Friends say he has two autistic grandsons, and watching the insensitivity the boys endured gave him a kind of collateral distaste for those who would marginalize gays. McDonald, entirely in character, responded to criticism by announcing that if doing the right thing costs him his seat, “They can take the job and shove it.” That did not sit well with some local Republican leaders, but it’s the kind of directness his constituents seem to like.

Jim Alesi, who formerly had a business operating laundry rooms in apartment buildings and dormitories, has been in politics for 23 years. He represents a swath of the Rochester area that’s more white-collar than blue-. When the Senate rejected gay marriage in 2009, Alesi toed his party’s line, but he held his head in visible distress, in part because it felt like a betrayal of his friend Thomas Duane, the Senate’s only openly gay member. “I promised myself then that I would never vote no on this issue again,” he told me. And because his relatively affluent electorate leans moderate on social issues, the vote was not likely to fire up a huge reaction. Unfortunately for Alesi, he has other liabilities — more on those later — and he knows that some in his own party, not just the Conservatives, would like to throw him overboard.

Mark Grisanti should be the most endangered Republican in the Senate. He is a freshman, an Italian Catholic Republican in a slice of the Buffalo region that is five-to-one Democratic and nearly 40 percent black. He won his seat by a mere 519 votes over an incumbent African-American Democrat, Antoine Thompson. Thompson supported gay marriage, not a popular view in the black churches of Buffalo.

Grisanti didn’t make a big deal of marriage in his campaign, but he told people he was in the man-and-a-woman camp, which probably bought him a smattering of black support. Moreover, Grisanti was listed on the ballot as the candidate of the Conservative Party in addition to being the Republican nominee, and he reaped 4,368 votes on the Conservative line.

So it is not a stretch to suggest that, between Conservative and black votes, Mark Grisanti owes his seat to the fact that he identified himself as a “no” vote on gay marriage. It is also not a stretch, as you will see, to say that if he wins re-election, it will be because he changed his mind.

The choice of a gay rights tour guide in Buffalo was obvious. Kitty Lambert and her partner were the state’s first gay newlyweds. When the law went into effect, she and Cheryle Rudd — both longtime gay rights activists and, as Lambert likes to say, “two fat grandmothers” — drove from their home in Buffalo up to Niagara Falls for a midnight ceremony. Lambert grew up Mormon, endured a series of husbands in the effort to live up to her religion’s expectations and came out as a lesbian in her 30s. Between them, she and Rudd have five grown children and 15 grandchildren.