New York state Senator Roy McDonald of Saratoga County has conceded to losing his GOP primary race.

McDonald was among the four Republicans who last year crossed the aisle to vote with all but one Democrat to legalize gay marriage in New York, making it the most populous state yet to do so. Senator Mark Grisanti of Buffalo won his primary with a comfortable margin, while Stephen Saland of Poughkeepsie claimed victory with only 107 votes to spare. James Alesi of Rochester, the fourth senator, retired.

McDonald lost his primary to a more conservative candidate, Kathy Marchione.

“I am very proud of my time in public service,” McDonald said in a 3-page statement. “Standing up for the communities I represented was always my first priority. I have been a senator for all people.”

The incumbent clung on as officials began counting paper ballots this week. But he fell further behind as the week progressed.

Marchione, the Saratoga County clerk, will face on November 6 an openly gay Democrat who is married, Robin Andrews.

McDonald said he would not pursue a third-party bid to hold on to his seat, a move which benefits Marchione by consolidating conservative votes in her name.

“I believe maintaining the Republican majority in the New York State Senate will continue to positively change state government,” he said. “It is important to recognize the need for checks and balances in our democracy, which can only be assured by a multiparty system.”