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Republican presidential candidates are joining New Hampshire's intensifying gay marriage debate -- whether they like it or not.

State lawmakers plan to take up a measure to repeal the law allowing same-sex couples to wed and a vote is expected at some point in January -- the same month as New Hampshire holds the nation's first Republican presidential primary contest. Already, candidates have been put on the spot over the divisive social issue when most, if not all, would rather be talking about the economy, voters' No. 1 concern.

The impending focus on gay marriage carries risk for several of White House contenders -- including former Massachusetts Gov. Mitt Romney, Texas Gov. Rick Perry and former businessman Herman Cain -- whose inconsistencies on the topic are well documented.

Recent polls have shown former House Speaker Newt Gingrich at or near the top of the field, along with Romney. With a little less than six weeks to go until the lead-off Iowa caucuses, people are listening to the former nemesis of Bill Clinton and would-be challenger to President Barack Obama.

But this issue may cause Gingrich problems. Earlier in the fall, he told an Iowa audience that gay marriage is a "temporary aberration" likely to go away because it defies convention. Gingrich, who has been married three times, has a half-sister in a same-sex marriage.

"The truth is that you're living in a world that no longer exists," Candace Gingrich-Jones wrote the former speaker in a letter posted on the Huffington Post in 2008: "In other words, stop being a hater, big bro."

The Republican candidates' increasingly vocal support for "traditional marriage" also threatens to alienate a growing number of younger Republicans and independents here who support legal recognition of same-sex couples. That note of divisiveness could bode poorly for the eventual Republican challenger to Obama in the general election.

Even so, the Republican candidates aren't shying away from the topic as they run for the nomination of a party dominated by conservatives and pushed further to the right by the tea party over the last few years.

"As conservatives, we believe in the sanctity of life, we believe in the sanctity of traditional marriage, and I applaud those legislators in New Hampshire who are working to defend marriage between one man and one woman realizing that children need to be raised in a loving home by a mother and a father," Perry told a New Hampshire audience recently, becoming the latest contender to address gay marriage directly.

Although the issue hasn't yet become a regular talking point on the campaign trail, most Republican candidates declare support for the effort to repeal the law. And groups like the National Organization for Marriage hope to force the presidential contenders to publicly embrace the repeal.

Romney was the Massachusetts governor when his state legalized gay marriage. The Romney administration, as directed by the courts, granted nearly 200 same-sex marriage requests for gay and lesbian couples in 2005.

Campaign spokesman Ryan Williams said the former governor had little choice but to follow the state Supreme Court ruling at the time. He noted his candidate's consistent opposition to both civil unions and gay marriages, adding that Romney openly supports the New Hampshire repeal effort.

But Romney has reversed himself on whether gay marriage should be addressed at the state or federal level.

This past June, he said during a debate that he favors a federal constitutional amendment banning the practice. That's been his position at least since the beginning of his 2008 presidential bid, when he was the only major Republican candidate to support such an amendment.

But as a Massachusetts Senate candidate back in 1994, Romney told a Boston-area gay newspaper that same-sex marriage is "a state issue as you know -- the authorization of marriage on a same-sex basis falls under state jurisdiction." Aides say it's unfair to scrutinize

Romney's position in 1994 -- when there was virtually no discussion of a federal amendment. And they suggest Romney's rivals have far more blatant inconsistencies in recent months.

Both Perry and Cain have drawn conservative criticism for recent comments related to gay marriage.

Asked in mid-October whether he supports a federal marriage amendment, Cain told the Christian Broadcasting Network that federal legislation is necessary to protect traditional marriage. That seemed to be a direct contradiction from his statement of just six days earlier, when he told "Meet the Press" host David Gregory that states should be allowed to make up their own minds.

"I wouldn't seek a constitutional ban for same sex marriage, but I am pro traditional marriage," Cain told Gregory.

In Perry's case, the Texas governor says he supports the New Hampshire repeal. But in July he said that New York's move to legalize gay marriage was "fine by me." A week later, facing social conservative criticism, he walked back the comments.

"It's fine with me that the state is using their sovereign right to decide an issue. Obviously gay marriage is not fine with me," he said then.