The political price for supporting same-sex marriage can be hard to predict. Four years ago, Assemblywoman Teresa R. Sayward, a Republican and a Catholic from a conservative district in the Adirondacks, voted in favor of same-sex marriage after making an impassioned speech about her son’s struggle with his gay identity.

“The night I took the vote the first time, I was told by my Republican colleagues that I would never get elected again,” she said. Since then, Ms. Sayward has been re-elected twice…

Bob Wood, 72, a Democrat and the captain of an Erie Canal cruise boat, said Mr. Alesi’s vote “showed real courage and leadership.” Mr. Wood worships with Mr. Alesi at Spiritus Christi Church, a Catholic congregation that broke with Rome in order to support gay men and lesbians, as well as women in the clergy.

But the reception in Mr. Alesi’s own party remains chilly.

“He’s not honest,” said Ray Akey, 66, a retired sales engineer and a Republican who had voted for Mr. Alesi in the past. He said he would not again — “Not after what he did to those people,” he said, referring to the lawsuit — but also because of the same-sex marriage vote.

Asked to sum up his feelings about his senator, Mr. Akey said: “It’s not real pretty. I’d have to put some cuss words in there.”