Top GOP donor Paul Singer is helping back a new super PAC “to encourage Republican candidates to support same-sex marriage,” according to a column in Sunday’s New York Times.

One race it might have an effect on: the re-election bid of vulnerable eight-term Rep. John Tierney (D-Mass.) against former state Sen. Richard Tisei (R), a longtime supporter of gay marriage equality.

“Tisei is one type of candidate who might draw financial help from Singer’s super PAC, which, according to Singer, will soon have a budget ‘of a few million dollars,'” columnist Frank Bruni wrote in the Times piece.

Tisei has outriased Tierney in both the fourth quarter of 2011 and the first quarter of this year. But the Democratic Congressional Campaign Committee recently booked $3.67 million of television advertising in the Boston media market, which could be used to bolster Tierney.

However, if a super PAC decides to play in that race as well, it could change the 6th district contest’s dynamics.

Tisei, openly gay, is considered a strong candidate, while Tierney has been weakened by his wife’s and brothers-in-law’s legal troubles.

But Tierney, also a strong supporter of same-sex marriage and gay rights, has a fundamental and very powerful advantage: He is Democrat in a state that hasn’t elected a Republican to Congress since 1994.

His campaign knocked Singer’s new PAC.

“The fact that a New York Wall Street billionaire feels the need to protect Republicans from the right-wing majority of their own party shows what most Americans already recognize: that the Republicans in Congress are the ones that have fought tooth and nail against equality for LGBT Americans,” Tierney campaign manager Matt Robison said in an email to Roll Call.

“As [Rep.] Barney Frank [D-Mass.], the most recognized gay American in Congress, said just yesterday, ‘If Mr. Tisei and others are successful in keeping John Boehner and Eric Cantor as the leaders of the House of Representatives, forget any possibility of anything happening that in any way advances LGBT rights,'” Robison added.

Tisei campaign manager Paul Moore said Tisei’s campaign was focused on its own efforts, but he praised Singer and former Republican National Committee Chairman Ken Mehlman, who also favors gay marriage equality and was quoted in Times column.

“Ken Mehlman and Paul Singer are very well known for their support of officeholders and candidates who support equal rights, particularly in New York state,” Moore said in an email to Roll Call. “Richard’s focus remains solely on his own campaign and the hard work it takes for him to raise the resources to oust a very entrenched incumbent.”

Roll Call rates the race as Leans Democratic.