It looks like there could be trouble for a couple of state Senate Republicans who voted in favor of same sex marriage last year. As Capital Tonight's Nick Reisman reports, there votes could come back to bite them politically.

STATEWIDE -- Their votes in favor of same-sex marriage garnered them praise and campaign cash from advocates. But two of the four Republican senators who broke ranks and voted for the law are now facing challenges from their right flank.

Assemblyman Steve McLaughlin, a Republican from the Capital Region, is gearing up to face Senator Roy McDonald. Senator Mark Grisanti, a Buffalo freshman, lost the coveted endorsement last week of the Erie County Conservative Party.

"If you take a look what was accomplished in 2011 and looking forward in 2012, I am confident that we as western New Yorkers and across New York state are a lot better off than we are now than they were in 2009 and 2010," said Mark Grisanti, Senator from Buffalo.

McLaughlin, who said Wednesday in telephone interview that he was planning to make a decision on the race soon, is picking up support from the Saratoga County GOP establishment.

It's a potentially troubling development for Senate Republicans, who hold a narrow 32 to 29 majority. But lobbyists opposed to gay marriage said the opposition to the incumbents is more complicated than just their yes votes.

"Particular with Senator McDonald it's an issue of really a flip flop on tax increases, there's been some union issues there that Republican voters are concerned about. In Buffalo with Grisanti it's a question of integrity. People there are saying if you can't trust him on the vote for same-sex marriage, what can you trust him on," said Rev. Jason McGuire, from NYers For Constitutional Freedoms.

However, the senators have a powerful and wealthy ally in New York City Mayor Michael Bloomberg. After the vote, Bloomberg showered the four GOP senators, including Jim Alesi and Stephen Saland, with the maximum campaign contribution.

"Well I can't go up there and vote for them. I vote in New York City. But I've certainly supported them financially. I've done fundraiser and gone to fundraisers for them. I've encouraged friends to do that. I just have never believed it's the government's business who you marry and I think we New Yorkers should stand proud. No matter what we believe personally getting the government out of making that decision was the right thing to do," said Mayor Michael Bloomberg.

Conservative activists remain upset that majority Republicans in the Senate allowed a vote on the gay marriage bill to occur in the first place. But part of their calculus may have been letting the issue go this year in a difficult election cycle and not face the wrath of well-financed advocates on the other side of the issue.