NEW YORK (AP) – Intrigued by divisions within conservative ranks, gay-rights strategists are trying to portray a proposed constitutional ban on same-sex marriage as a radical step that true conservatives should oppose.

The Human Rights Campaign, a national gay rights group, is targeting conservatives with a radio and print ad campaign in 10 areas, including Omaha, Nebraska; Indianapolis; Tampa, Florida; Milwaukee; Las Vegas; and Philadelphia.

“Be conservative with the Constitution,” the ads say. “Don’t amend it.”

Disagreements among conservatives have emerged in recent months over the proposed Federal Marriage Amendment, which would stipulate that marriage is only between a man and woman.

Some want the measure toughened so it would bar same-sex civil unions and domestic partnerships as well as gay marriages. Other conservatives, including several prominent columnists and politicians, say the Constitution is the wrong place to address contentious social problems and contend the measure would infringe on states’ rights.

The critics include former U.S. Rep. Bob Barr, a Republican who called the amendment “needlessly intrusive,” and columnist George Will, who said it would unwisely override state responsibility for marriage law.

Tony Perkins, president of the pro-amendment Family Research Council, said he respected some of the criticism. However, he said the amendment was the only effective option now that the Massachusetts Supreme Judicial Court has ruled the state cannot deny marriage rights to same-sex couples.

“It’s no longer a theoretical discussion about ‘What ifs?”” Perkins said in a telephone interview. “It’s a public policy crisis.”

President George W. Bush addressed the issue during an interview with ABC News last month, but his comments confused and dismayed many conservative activists.

On the one hand, Bush said, “If necessary, I will support a constitutional amendment which would honor marriage between a man and a woman, codify that.”

However, in what some conservatives perceived as an endorsement of civil unions, Bush added, “The position of this administration is that whatever legal arrangements people want to make, they’re allowed to make, so long as it’s embraced by the state or at the state level.”