U.S. Central Command Commander-nominee Marine Corps Gen. James Mattis, center, smiles on Capitol Hill in Washington, Tuesday, July 27, 2010, prior to testifying before the Senate Armed Services Committee hearing on his nomination. (AP Photo/Alex Brandon)
Senate Armed Services Committee Chairman Sen. Carl Levin, D-Mich., left and the committee's ranking Republican Sen. John McCain, R-Ariz., right, question Marine Corps Gen. James Mattis, center, on Capitol Hill in Washington, Tuesday, July 27, 2010, during the committee's hearing on Mattis' nomination to head the U.S. Central Command. (AP Photo/Alex Brandon)
U.S. Central Command Commander-nominee Marine Corps Gen. James Mattis arrives on Capitol Hill in Washington, Tuesday, July 27, 2010, to testify before the Senate Armed Services Committee hearing on his nomination. (AP Photo/Alex Brandon)
** FILE ** Gen. David Petraeus testifies on Capitol Hill in Washington on Tuesday, June 29, 2010, before the Senate Armed Services Committee hearing to be confirmed as President Obama's choice to take control of forces in Afghanistan. (AP Photo/Pablo Martinez Monsivais)
Gen. David Petraeus testifies on Capitol Hill in Washington, Tuesday, June 29, 2010, before the Senate Armed Services Committee hearing to be confirmed as President Obama's choice to take control of forces in Afghanistan. (AP Photo/Pablo Martinez Monsivais)
The Senate Armed Services Committee's ranking Republican, Sen. John McCain, left, R-Ariz., left, accompanied by fellow committee members, Sen. Joseph Lieberman, I-Conn., and Sen. Lindsey Graham, R-S.C., walk to a news conference on Capitol Hill in Washington, Wednesday, June 23, 2010, to discuss the confirmation hearings for Gen. David Petraeus. (AP Photo/Alex Brandon)
Senate Armed Services Committee members, from left, Sen. John McCain, R-Ariz., the committee's ranking Republican, Sen. Lindsey Graham, R-S.C., and Sen. Joseph Lieberman, I-Conn., take part in a news conference on Capitol Hill in Washington, Wednesday, June 23, 2010, to talk about confirmation hearings for Gen. David Petraeus. (AP Photo/Alex Brandon)
Gen. David Petraeus, commander of the U.S. Central Command, testifies before the Senate Armed Services Committee in Washington, Wednesday, June 16, 2010. (AP Photo/Drew Angerer)
Gen. David Petraeus, commander of the U.S. Central Command, testifies before the Senate Armed Services Committee in Washington, Wednesday, June 16, 2010. (AP Photo/Drew Angerer)
Army Gen. David Petraeus, U.S. Central commander, is surrounded by staff after appearing to collapse on Capitol Hill in Washington on Tuesday, June 15, 2010, while testifing before the Senate Armed Services Committee. (AP Photo/Evan Vucci)
Army Gen. David Petraeus, U.S. Central commander, rises out of his chair after appearing to collapse on Capitol Hill in Washington on Tuesday, June 15, 2010, while appearing before the Senate Armed Services Committee. (AP Photo/Evan Vucci)
Army Gen. David Petraeus, U.S. Central Commander, is led away by staff after appearing to collapse on Capitol Hill in Washington on Tuesday, June 15, 2010, while testifying before the Senate Armed Services Committee. (AP Photo/Evan Vucci)