ALBANY — The Working Families Party, which has endorsed activist Cynthia Nixon for governor over Gov. Andrew M. Cuomo, said Tuesday that it won’t play a “spoiler’s role” in November that could split the Democratic vote and help a Republican nominee win.

“We’re committed to not spoiling,” said Bill Lipton, state director of the Working Families Party, a coalition of progressive voters and labor.

Nixon has refused to say if she would run on a minor party line in November if she loses the Democratic primary in September to Cuomo. On Saturday, when asked about running in November only on the WFP line if she loses the Democratic primary, Nixon said only: “We will win.”

Nixon’s entry to the race was welcomed by Republicans who saw a possible split of the Democratic vote in November that could allow the GOP to win with a plurality in the state dominated 2:1 by Democratic voters.

“Republican operatives shouldn’t be getting excited about this,” Lipton said Tuesday.

Avoiding the spoiler’s role has traditionally taken a few forms. A minor party candidate can effectively suspend a campaign in the general election to avoid siphoning votes or could pursue an aggressive campaign, but only if the allied major party candidate has a wide, unassailable lead. In past years, some minor parties have also thrown their support to major party candidates late in the campaign.

The Working Families Party endorsed Nixon on Saturday, but will meet again in September. In past years, some minor parties have thrown their support to major party candidates late in the campaign.

“We both agree to take the interests of working people very seriously,” Lipton said Tuesday. “The Working Families Party has a 20-year history of not spoiling.”

Republicans have not yet nominated a candidate. Dutchess County Executive Marc Molinaro and state Sen. John DeFrancisco (R-Syracuse) are campaigning for the nomination.