Utah Republican Party Chairman Joe Cannon said Romney could help burnish his image as a defender of conservative values with his opposition to gay marriage, which became legal in Massachusetts last May on a ruling from the state's highest court. Romney also opposes Vermont-style civil unions but backs some limited domestic partner benefits, such as hospital visitation rights.

"From my perspective, he's taken a very strong and aggressive approach to saying we don't like this law, it's not the will of the people," Cannon said. "His recent statements on stem cell research are also going to go right to the heart of the conservative pro-life constituency."

Romney has said he supports embryonic stem cell research using frozen embryos that would otherwise be discarded by fertility clinics. In a Times interview, he said he wants to outlaw the cloning of embryos for their stem cells.

Not all Republicans are enamored of Romney.

The Log Cabin Republicans, a national gay advocacy group, said the Romney who preached tolerance during the 2002 gubernatorial campaign is fading from view.

"What happened to the Mitt Romney who ran for governor supporting employment non-discrimination, hate crimes legislation, domestic partnerships, and civil union-like benefits for gay couples?" said Log Cabin Massachusetts president Ken Sanchez.