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The Massachusetts court ruling demanding the approval of same-sex marriages is bound to have political implications on the campaign trail as Democratic contenders continue to vie for their party's nomination to run against President Bush in November.

"I would think this will be the hot button social issue of this campaign," said Fox News senior judicial analyst Andrew P. Napolitano (search). "Like a lot of these social issues it will wind up in the Supreme Court."

In his State of the Union address last month, President Bush (search) essentially promised to use the Constitution to knock down any court rulings allowing same-sex marriages.

"I believe we should respect individuals as we take a principled stand for one of the most fundamental, enduring institutions of our civilization," Bush said. "The only alternative left to the people would be the constitutional process. Our nation must defend the sanctity of marriage," he said.

In a December interview with ABC News, Bush criticized the Massachusetts court's original decision in November when it said that denying gay couples the right to marry was unconstitutional. In its follow-up decision Wednesday, the court said that only marriage -- and not the concept of civil unions -- would be acceptable to satisfy its constitutional concerns.

"The court, I thought, overreached its bounds as a court," Bush said. "It did the job of the Legislature."

In the Democratic race for president, front-runner John Kerry (search), has stopped short of endorsing gay marriage but has supported gay civil unions and called for states to determine the issue for themselves, rather than the federal government.

Kerry, a Massachusetts senator who has won seven out of nine primaries and caucuses so far this primary season, voted against the Defense of Marriage Act of 1996. Known as DOMA, the law denies federal recognition of same-sex marriages and gives states the right to refuse to recognize same-sex marriages licensed in other states.

"I strongly support civil unions. I believe same-sex couples should be granted full and equal protection under the law, including access to health insurance, family medical leave, bereavement leave, hospital visitation, survivor benefits, and other basic legal protections that all families deserve," Kerry has said in interviews.

Michael Meehan, a senior adviser for the Kerry campaign, told Fox News that although Kerry has opposed gay marriage, "he thinks there's a lot of gay bashing going on and he won't stand for that. He believes there's a lot of rights that need to be protected."

Some political experts said Kerry could be particularly vulnerable on the gay marriage issue because he is from Massachusetts and Boston is the location for the Democratic national convention this summer.

"I'm willing to guess that the opposition will try to make this a significant issue and will try to pin that issue on him [Kerry] as the donkey," Richard Fisher (search), a former U.S. trade deputy, told Fox News on Wednesday.

Jim Lake, a Republican pollster, said although Kerry has not yet issued a formal response to Wednesday's decision, he has in the past supported Massachusetts statutes.

"But the American people, it's not just Democrats … all across the board are going to be incensed by it [Massachusetts court decision] and it will be heightened in its tension at the convention and I think there's going to be a price to pay for Kerry," Lake said.

A majority of Americans continues to oppose same-sex marriage, and nearly half oppose civil unions, according to a FOX News poll conducted in the days following the Supreme Judicial Court ruling in Massachusetts.

That poll showed that 66 percent of Americans oppose and 25 percent favor same-sex marriage.

North Carolina Sen. John Edwards (search), who beat Kerry in Tuesday's South Carolina primary, has said same-sex marriage decisions should be left up to the states and that he supports partnership benefits. He opposes gay marriage, however.

"I believe in the equal dignity of all Americans and support partnership benefits for gays and lesbians in long-term relationships," Edwards has said. "States should be free to decide if they want to create civil unions with benefits akin to marriage. If states establish these civil unions, then the federal government should respect their decision and offer benefits along these lines."

Retired Army Gen. Wesley Clark (search), who won Oklahoma's primary Tuesday night, welcomed the original Massachusetts court decision.

But the former NATO commander has said that whether civil unions are defined as a "marriage" or not is up to state legislatures and churches to decide. He wants to give same-sex couples legal rights and federal employees the right to declare same-sex partners as beneficiaries.

"Equal rights under the law is one of the fundamental tenets of our democracy," Clark has said. "Moreover, it is in the best interest of America to promote stable communities and families - this includes both heterosexual and same-sex families."

Howard Dean (search), who is lagging in the polls, supports same-sex civil unions and argues that gay marriage is not an issue for the federal government to decide. He opposes the Defense of Marriage Act. While he was governor of Vermont, Dean signed the landmark bill legalizing civil unions for gay couples.

"The overwhelming evidence is that there is very significant, substantial genetic component to it," Dean said in a newspaper interview last month. "From a religious point of view, if God had thought homosexuality is a sin, he would not have created gay people."

The Associated Press contributed to this report.