By Amy Lorentzen

A.P. writer

DES MOINES, Iowa—An Iowa county judge’s ruling knocking down the state’s same-sex marriage ban stirred up the presidential race last week as Republicans jostled to stake out a position with the state’s conservative voters in mind.

Mitt Romney was the first to seize on the ruling, promptly denouncing the decision.

The former Massachusetts governor’s swift criticism served to bolster the conservative image his campaign has been working hard to promote to Iowa’s Republican voters. Romney stressed his support for a federal amendment that would ban same-sex marriage, a stand that distinguishes him from his top rivals, who have said they prefer to leave such decisions to the states.

“This once again highlights the need for a Federal Marriage Amendment to protect the traditional definition of marriage as between one man and one woman,” Romney said in a statement shortly after the ruling was made.

Sen. Hillary Rodham Clinton was the first Democrat to offer a reaction. Taping an appearance on “The Ellen DeGeneres Show” Aug. 31, Clinton said she favors civil unions “with full equality of benefits.” But she said the question of same-sex marriage should be left up to the states.

“The states have always determined age of marriage, other conditions and over time we’ve gotten rid a lot of discrimination that used to exist in marriage laws,” she said. “That’s now happening. People are making decisions—civil unions, marriage. They’re deciding in the states and I think that’s the appropriate place for that to be.”

A spokesman for Democrat Barack Obama said the senator “believes these matters should be left to the states, which is why he opposes the Defense of Marriage Act.”

While most Democratic candidates have voiced support for same-sex civil unions, they have declined to back gay marriage, a stance that has created some tension with their gay supporters.

Republican White House hopeful John McCain called the ruling “a loss for the traditional family.”

“I have always supported the traditional definition of marriage as between one man and one woman,” he said. “The ruling of the court only reinforces my belief that we must have a president who is committed to appointing strict constructionists to the bench.”

Jarrod Agen, a spokesman for Rudy Giuliani, said the former New York mayor “believes marriage is between a man and a woman.” Giuliani has supported limited legal recognition for same-sex couples.

“It’s becoming increasingly clear why we need judges who interpret the Constitution rather than legislate from the bench,” Agen said. “It’s the reason why Rudy is committed to appointing strict constructionist judges in the vein of Alito, Roberts and Scalia.”

Former Sen. Fred Thompson, who will officially enter the GOP presidential race this week, has offered support for a federal amendment that would prevent states without gay marriage laws from having to recognize same-sex marriages from other states.

Dianne Bystrom, director of the Carrie Chapman Catt Center for Women and Politics at Iowa State University, said the ruling could fire up social conservatives.

“It will probably stir up the social conservatives in the state and make the climate better in Iowa for the most socially conservative of the presidential candidates,” she said. “That would be most of them, except (Rudy) Giuliani, I guess.”