President Bush paid tribute today to Gen. Richard B. Myers, the retiring chairman of the Joint Chiefs of Staff and the military's public face of the U.S. wars in Iraq and Afghanistan.

Bush said Myers, a 63-year-old Kansan who has been in the Air Force for 40 years, "helped design a broad and innovative military strategy to win the war on terror." He said Myers's "steady and practical" counsel helped design the plan for attacking Iraq and ousting dictator Saddam Hussein.

Myers's "leadership and flexibility were essential to the liberation of Iraq," Bush said, and he praised the general for helping to "unite more than 90 nations in the war on terror."

In an outdoor ceremony at Ft. Myer, in Arlington, Marine Gen. Peter Pace, 59, was sworn in to succeed Myers. The first Marine ever to hold the military's top job, Pace had served under Myers as vice chairman of the Joint Chiefs for 3 1/2 years, helping to manage the conflicts in Iraq and Afghanistan and furthering a reputation as a smooth political operator.

Bush said Myers, who took over the military's No. 1 post in the fall of 2001, possessed a "calm and reassuring presence coupled with sound judgment and fresh thinking and unflinching candor." He described Myers as a "kind and humble man who believes in serving a cause greater than himself."

Myers, a fighter pilot in Vietnam, told the gathering that "the stakes in the war on terrorism simply couldn't be higher. We're all in this together and we will win this war."

Navy Adm. Edmund P. Giambastiani Jr. succeeded Pace as the new vice chairman.

The selection of Pace and Giambastiani for the Pentagon's top military posts teams Defense Secretary Donald H. Rumsfeld with a pair of senior officers with whom he is very familiar.

Giambastiani, 56, served as Rumsfeld's senior military assistant for a year before becoming head of Joint Forces Command in 2002. Pace, a graduate of the U.S. Naval Academy, was sent to Vietnam as a lieutenant in the late 1970s and served as a platoon leader, winning a Bronze Star. In the early 1990s, he commanded Marines in Somalia, returning in 1993 after the failed raid that killed 18 Americans to help preside over an ignominious U.S. withdrawal.