BOSTON - Gov. Mitt Romney is trying to portray himself as a moderate on gay marriage in Massachusetts, while at the same time appearing more conservative to Republicans outside the state, critics say.

The Republican governor, in comments to GOP activists in South Carolina on Monday, took a hard line against both gay marriage and civil unions. But he failed to tell a gathering of Spartanburg County Republicans that for months he has backed a proposed amendment to the Massachusetts constitution that would provide same-sex couples "entirely the same benefits, protections, rights and responsibilities that are afforded to couples married under Massachusetts law."

"From day one, I've opposed the move for same-sex marriage and its equivalent, civil unions," Romney said on Monday.

Romney aides said the comments refer to Romney's initial strong opposition to both gay marriage and Vermont-style civil unions. During much of the gay marriage debate, Romney said he would only support very limited rights for same sex couples.

Both supporters and opponents of gay marriage say Romney, a possible Republican presidential contender in 2008, is trying to have it both ways.

"You can't say I'm for civil unions when you're in Massachusetts and say you're against them when you're out of Massachusetts. It just doesn't wash," said state Rep. Philip Travis, D-Rehoboth, a gay marriage opponent.

Romney's opposition to gay marriage has been lukewarm from the start, Travis said. "He never came out publicly and stood with us who were trying to get the pure bill through the Legislature. He just stayed in his office and made statements."

Gay activists said they also found Romney's statements puzzling.

"The governor's kind of bi about this issue. In one venue he swings for civil unions and in another venue he says he has always been against them," said Arline Isaacson of the Massachusetts Gay and Lesbian Political Caucus.

Early in the debate, Romney repeatedly stated his opposition to gay marriage and civil unions, saying those benefits should be reserved for heterosexual couples.

"Marriage is a fundamental and universal social institution," he wrote in a Wall Street Journal editorial. "That benefits are given to married couples and not to singles or gay couples has nothing to do with discrimination; it has everything to do with building a stable new generation and nation."

But during a crucial final vote last year, Romney officials urged more than a dozen Republican lawmakers to support the compromise version which included strong civil unions language.

Within moments of that vote, Romney told reporters he would ask the state Supreme Judicial Court to block gay marriages, then scheduled to begin May 17 under the court's landmark November 2003 ruling, until the process had a chance to play out.

The court instead allowed the marriages to go forward.

Ron Crews, one of the top crusaders against gay marriage in Massachusetts, said Romney supported the compromise because he needed the Legislature to take some action so he could ask the court to hold off on gay marriages until the amendment went to voters.

"We wound up encouraging lawmakers to vote for that language because we were trying to prevent May 17 from happening," Crews said. "Politically we had to do what we had to do to get an amendment passed, but now we are in a different situation."

Romney's political foes said Monday's speech was politically self-serving.

"I thought he was a bit strident. That was a speech for South Carolina, not for Massachusetts," said Attorney General Thomas Reilly, a likely Democratic challenger to Romney next year.

Reilly opposes gay marriage, but believes the state should move forward.