U.S. Army Sgt. Matt Radcliffe provides security during a patrol in the Adhamiyah District of Baghdad, April 20, 2008. Radcliffe is assigned to the 4th Infantry Division's 3rd Brigade Combat Team, 3rd Special Troops Battalion. U.S. Air Force photo by Tech. Sgt. William Greer

U.S. Navy Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, addresses service members enrolled at the National Defense University, on Fort Leslie J. McNair, Washington , D.C., April 22, 2008. Defense Dept. photo by Petty Officer 1st Class Chad J. McNeeley

Defense Secretary Robert M. Gates speaks during a media round table at the Pentagon, April 23, 2008, where he announced that the White House has nominated Army Gen. David H. Petraeus to be the next commander of U.S. Central Command. Defense Dept. photo by U.S. Navy Petty Officer 2nd Class Molly A. Burgess

U.S. Navy Seaman Christopher Tornay, a damage controlman fireman, shouts commands at Petty Officer 2nd Class Bryan Egolf during fire hose training on the forecastle of the guided-missile destroyer USS Lassen in the Pacific Ocean, April 21, 2008. U.S. Navy photo by Petty Officer 3rd Class Matthew R. White

Colombian special forces show counter insertion tactics to participants of the 75th Joint Civilian Orientation Conference outside Bogota, Colombia, April 22, 2008. Defense Dept. photo by U.S. Air Force Master Sgt. Kevin J. Gruenwald

Defense Secretary Robert M. Gates speaks with 1st Capt. Jason Crabtree while having dinner with cadets at the United States Military Academy at West Point, N.Y., April 21, 2008. Defense Dept. photo by Cherie Cullen

Defense Secretary Robert M. Gates meets with cadets at the indoor rifle range at the U.S. Military Academy at West Point, N.Y., April 21, 2008. Defense Dept. photo by Cherie Cullen

Colombian special forces members show counter insertion tactics to participants of the 75th Joint Civilian Orientation Conference outside Bogota, Colombia, April 22, 2008. Defense Dept. photo by U.S. Air Force Master Sgt. Kevin J. Gruenwald