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WASHINGTON -- Marine Corps Commandant Gen. James Conway became the highest ranking officer to break publicly with President Obama in his push to repeal the law that bans gays from serving openly in the military.

"I think the current policy works," Conway told a Senate panel reviewing the policy known as "Don't Ask, Don't Tell." "At this point... my best military advice to this committee, to the [Defense] Secretary, and to the president would be to keep the law such as it is."

President Obama made a campaign promise to change the law that prohibits gays from serving, and earlier this month he made progress towards that goal when Defense Secretary Robert Gates and Adm. Michael Mullen, chairman of the Joint Chiefs of Staff, announced their support. Mullen told Congress on Feb. 2 that allowing gays and lesbians to serve openly is "the right thing to do."

"For me, personally, it comes down to integrity -- theirs as individuals and ours as an institution," Mullen said.

In that same hearing, Gates announced he'd appointed a "high-level working group" to study the issue and report back by the end of the year out how best to change the law. Gates said if the law is repealed, integration of gays would happen slowly and could take as many as five years.

But Conway hasn't been the only top general to express his concern. On Tuesday, the Air Force Chief of Staff, Gen. Norton Schwartz, told the House Armed Services Committee that now "is not the time to perturb the force," a force he described as "stretched by demands in Iraq and Afghanistan."

Also on Tuesday, the Army's chief of staff, Gen. George Casey, testified to a Senate panel that he had "serious concerns" about the impact of a repeal. Like Schwartz, Casey expressed apprehension over changing the rules while troops are already stressed from the two wars. Casey said he was worried this could poorly effect "readiness and military effectiveness."

On Thursday, Pentagon spokesman Geoff Morrell attempted to downplay any conflict among the military leadership.

"I saw, I think, universal agreement among the chiefs that this time is necessary," Morrell told reporters in reference to the review period. "And I think you saw a few of them caution some members that it would be in their opinion inadvisable to move before this review has been completed."

The military has never before conducted its own study on how to best incorporate openly homosexual members, but a rare poll of the active duty force says a majority opposes the idea. In November, "The Military Times" surveyed its active duty subscribers and found that 51 percent are opposed to gays serving openly, while 30 percent favor it. 20 percent declined to comment. The same poll found the number of retirees who oppose the idea jumped by 7 percent.

Public opinion is a different matter. Both a recent "Fox News Opinion Dynamics Poll" and the same "The Military Times" survey found a large majority of civilians favor the idea of allowing gays to serve. In the Fox News poll, it was split 61 to 30 percent in favor, while the "Military Times" showed 69 percent favor it and 26 percent don't.

Despite public opinion, Obama ultimately will rely on congressional votes for passage. An endorsement from Gates and Mullen was a step in that right direction, but it's possible this recent show of doubt will hurt the the president's chances for a repeal. Sen. Joe Lieberman, I-Conn., who is looking to draw up the legislation, has yet to find a co-sponsor.