WASHINGTON (AP) — President Barack Obama sharply rebuked his Republican rivals, saying anyone who wants to be commander in chief must support the entire U.S. military, including gay service members.

A combative Obama on Saturday criticized Republican presidential candidates for staying silent when the crowd at a recent debate booed a gay soldier serving in Iraq who asked a question of the contenders via videotape.

“You want to be commander in chief? You can start by standing up for the men and women who wear the uniform of the United States, even when it’s not politically convenient,” Obama said during remarks at the annual dinner of the Human Rights Campaign, the nation’s largest gay rights organization.

Referencing the boos at the Sept. 22 Republican debate, he said: “We don’t believe in standing silent when that happens.”

One of the Republican candidates, businessman Herman Cain, said Sunday that he should not have stayed silent after the debate audience booed the gay soldier. He said it would have been “appropriate” for him to have defended the soldier.

Cain said it wasn’t immediately clear to him what had drawn the audience’s scorn, adding, “I happen to think that maybe they were booing the whole ‘don’t ask, don’t tell’ repeal more so than booing that soldier.”

The so-called “don’t ask, don’t tell” policy barring gays from serving openly in the military was officially lifted last month.

Separately, Sen. John McCain, Obama’s opponent in the 2008 presidential race, said that the Republican candidates at the debate should have defended the soldier. “The fact is we should honor every man and woman who is serving in the military and should in no way treat them with anything but the highest regard,” he told CBS’ “Face the Nation.”

McCain added that the candidates may have been thinking about how to respond to the soldier’s question rather than paying attention to the booing. “I would bet that every Republican on that stage did not agree with that kind of behavior,” he said.

Last December, McCain led Senate opposition to the repeal of the restriction on gay service.

In his speech Saturday night, Obama touted his administration’s efforts to repeal the military’s ban on openly gay service members, as well as his orders to the Justice Department to stop enforcing a law defining marriage as between one man and one woman.

But, as expected, Obama stopped short of endorsing gay marriage, saying only that “every single American deserves to be treated equally in the eyes of the law.”

Obama has said his views on gay marriage are “evolving”, but for now he only supports civil union.

Obama’s position on gay marriage has become a sore point for some gay activists who say they’re otherwise pleased with the president’s handling of issues important to them. Some of the president’s backers say he could be wasting a chance to energize key segments of his base, including young people, if he doesn’t publicly advocate for gay marriage.

“If he doesn’t, he could be missing an opportunity to mobilize voters who need to be inspired to vote for him,” said Doug Hattaway, a Democratic consultant.

The president’s position on gay marriage puts him at odds with some of his supporters. Numerous recent polls suggest a slight majority of Americans favor giving same-sex couples the right to marry, and support is highest among Democrats and young people.

Obama has acknowledged that public support for gay marriage is building. During a meeting with liberal bloggers last October, he said “it’s pretty clear where the trend lines are going.”

Obama aides have given no indication of where the president’s evolution on gay marriage stands. And some gay rights advocates believe political considerations could keep Obama from publicly backing gay marriage until after the November 2012 election.

Joe Sudbay, among a group of bloggers who met with Obama last year, said most gay rights advocates won’t vote against Obama if he stops short of backing gay marriage. But he said they may be less likely to volunteer their time and money to the campaign.

“He might not lose votes, but he won’t gain enthusiasm,” said Sudbay, deputy editor of AmericaBlog.com.

While gay rights advocates may not be getting everything they want from the president, they see little support for their cause among the field of Republican primary contenders.

Most top Republican presidential candidates, including former Massachusetts Gov. Mitt Romney and Texas Gov. Rick Perry, favor limiting marriage to unions between one man and one woman.

Fred Sainz, the Human Rights Campaign’s vice president for communications, said he expects Obama to eventually declare his support for gay marriage. And even if that doesn’t happen before next year’s election, he said the president’s other actions on gay rights issued should not be ignored.

“He really has been an incredible champion for the issues that are important to us,” Sainz said. “It’s fair to say we’ve made more progress in the past two years than we have in the past 40 years combined.”

In his remarks Saturday night, Obama implored the supportive crowd of 3,200 to stand with him in his re-election campaign, declaring: “This is a contest of values.”

___

Associated Press writer Julie Pace can be reached at http://twitter.com/jpaceDC

Copyright 2011 The Associated Press.