BOSTON (AP) – In the battle over marriage for gays and lesbians, liberals have been front and center, pushing to give gays and lesbians the right to wed.

But there is at least a small block of conservatives who are on the same page, often for different reasons: They’re loath to tinker with a constitution, for one, or they want to see more people – gay or straight – make commitments.

The stance is a departure from that of most conservatives, a division that supporters of marriage for gays and lesbians hope to exploit.

“I don’t see the response to gay marriage as unified at all on the conservative side,” said Glenn H. Reynolds, a supporter of marriage for gays and lesbians and publisher of the generally conservative blog Instapundit.com.

Most recent polls have shown fairly wide skepticism about marriage for gays and lesbians. Democrats are nearly evenly split on the matter, while most Republicans oppose it.

That split was evident in the Massachusetts Legislature when three proposed amendments to the state constitution that would have banned marriage for gays and lesbians lost by a handful of votes each time. (Each amendment also would have allowed civil unions in some form.)

After two days of intense debate that went well into the evening, legislators failed to reach a consensus and decided to recess until next month.

If lawmakers pass such a constitutional amendment this year, it would put it on course to end up on the ballot in November 2006 – two years after court-ordered weddings are to begin taking place in the state.

A vocal contingent of conservatives are furious that “activist” judges have forced a revision of the law, and adamant that the millenia-old institution of marriage should be reserved for heterosexual couples.

Marriage for gays and lesbians would not be “the end of civilization,” said David Horowitz, a prominent conservative who once opposed a constitutional amendment outlawing marriage for gays and lesbians but has changed his mind in light of the Massachusetts decision. “But I am an opponent of judicial tyranny. And I think there’s a lot of conservatives like me.”

But while many conservatives oppose activist judges, they also resist tinkering with the state and federal constitutions. On states-rights grounds, prominent right-leaning columnists like George Will have opposed a proposed federal amendment, as have key lawmakers who otherwise oppose marriage for gays and lesbians, like Rep. Bob Barr, R-Ga.

A few conservative commentators have articulated a case that goes beyond opposing a constitutional amendment, and actually support marriage for gays and lesbians.

“The conservative course is not to banish gay people from making such commitments. It is to expect that they make such commitments,” David Brooks wrote recently in The New York Times, praising the virtues of fidelity. “We shouldn’t just allow gay marriage. We should insist on gay marriage.”

Sensing chinks in the armor, gay-rights activists are appealing to family values or a hands-off approach to the Constitution.

The gay-rights group Human Rights Campaign has touted the virtues of marriage both for gay families and America in ads that ran in establishment newspapers like The New York Times and The Washington Post.

But in the ads it ran in places like Omaha and Indianapolis, Human Rights Campaign took a different tack, appealing to conservatives not to support a federal amendment banning marriage for gays and lesbians. In one, an elderly woman stares into the camera and says “I’m pretty conservative, but I can’t support amending the constitution over this.”

Nebraska is one of four states where voters have approved constitutional amendments banning same-sex unions.

Seth Kilbourn, HRC’s national field director, said his group believes the country’s conservative leadership is split on marriage for gays and lesbians. His group is trumpeting the message that amending the constitution to discriminate is wrong.

“Under that message falls the conservative argument: You don’t use the constitution to resolve these kinds of social debates,” Kilbourn said.

The Log Cabin Republicans, a group of gay and lesbian Republicans, is also focusing on the constitutional argument.

“We have found some conservative Republicans and a handful of senators, Democrats and Republicans, who are probably never going to be with us on equality but would probably cut their arm off before they’d mess with the constitution,” said Mark Mead, the group’s political director.

Social conservatives say such arguments betray the cause.

Genevieve Wood, vice president of communications for the Family Research Council, accuses Brooks and others of failing to be “true conservatives” when it comes to marriage for gays and lesbians.