Defense Secretary Gates may be gearing up to persuade President Bush to move toward a drawdown in Iraq. “I see signs of it,” a retired Army general, William Odom, who served in Vietnam and ran the National Security Agency under President Reagan, said. “Look at his assessments of the state of affairs out there. There is an elasticity to his position.”

The chairman of the Senate Armed Services Committee, Senator Levin, agrees. The Michigan Democrat said Mr. Gates’s public comments indicate that he is “playing a prodding role” within the Bush administration, aimed at “trying to prepare the way for a shift of course.”

Messrs. Levin and Odom say that Mr. Gates enjoys considerable leverage within the administration. The secretary has repaired relations with senior uniformed officers and members of Congress — two groups his predecessor, Donald Rumsfeld, alienated — and projects what he calls a “no happy-talk” tone about Iraq. That gives him credibility that may make Mr. Bush reluctant to reject his counsel.

“He has very strong cards to play, if he wants to play them,” said Mr. Odom, now with the Hudson Institute in Washington.

While Messrs. Odom and Levin are both longtime critics of the war, even one of its original supporters, a former Pentagon adviser, Kenneth Adelman, shares the view that Mr. Gates is likely to come down on the side of gradual disengagement.

“Bob Gates is a very realistic guy,” said Mr. Adelman, who backed the 2003 American-led invasion but now says the war has been mismanaged. “He will look at the situation and ask himself, ‘Can we win this?’ If the answer is, not really, he won’t be interested in sacrificing more American lives.”

Some analysts, such as Michael O’Hanlon of Washington’s Brookings Institution, say Mr. Gates will move cautiously, given the fierce commitment of Mr. Bush and Vice President Cheney to the Iraq enterprise.

“I think he’s going to be careful,” Mr. O’Hanlon said. “He knows it will be hard for the president to modify this strategy.”

Rep. Jack Kingston, a Georgia Republican who supports the current troop buildup in Iraq, said Mr. Gates should be buying more time for the military to do its work.

“Right now it’s the job for Gates to get out there and say, ‘Don’t expect miracles by September,”‘ said Mr. Kingston, whose district includes Fort Stewart, a major Army base near Savannah. “He needs to be out there articulating it.”

While Mr. Gates has expressed support for an eventual transition to a residual U.S. force that could help stabilize Iraq after most combat troops leave, he has been careful to keep his options open in his public statements.

“What I’m thinking in terms of is a mutual agreement where some force of Americans, mutually agreed, with mutually agreed missions, is present for a protracted period of time,” Mr. Gates said on May 31.

Asked yesterday during a news conference whether those who expect him to push for disengagement are right, Mr. Gates said: “I spent several decades as a Kremlinologist, and sometimes I got it right and sometimes I didn’t. I’ll leave it at that. They’ll find out.”

Mr. Gates, 63, comes from the “realist” school of foreign policy, symbolized by his long ties to Brent Scowcroft, the White House national security adviser during President George H.W. Bush’s presidency. After serving as Mr. Scowcroft’s deputy, Mr. Gates headed the Central Intelligence Agency.

If Mr. Gates chooses to weigh in on the side of reducing American forces, his moment is likely to arrive in September, when the U.S. military commander in Iraq, General David Petraeus, and the U.S. ambassador, Ryan Crocker, will issue a much-anticipated progress report on the war; the funding for military operations in Iraq will expire, and Republican lawmakers — who thus far have resisted efforts to force a change in course — will return to Washington after spending the August recess listening to war-weary constituents.

Mr. Gates arrived at the Pentagon just as Mr. Bush was formulating plans for a troop buildup and carried it out even as requests from field commanders increased it to 30,000 from 21,500.

“He climbed aboard a moving train,” Scowcroft said in an interview. “The policy was ongoing.”

Mr. Gates has said any judgment about the buildup, which has boosted U.S. forces in Iraq to 156,000, and what follows can’t come before autumn.