U.S. Army Gen. David H. Petraeus, commander of U.S. and NATO forces in Afghanistan, arrives on Capitol Hill in Washington on Tuesday, March 15, 2011, to testify before the Senate Armed Services Committee on the situation in Afghanistan. At left is Defense Under Secretary for Policy Michele Flournoy. (AP Photo)

U.S. Army Gen. David H. Petraeus, commander of U.S. and NATO forces in Afghanistan, arrives on Capitol Hill in Washington on Tuesday, March 15, 2011, to testify before the Senate Armed Services Committee on the situation in Afghanistan. At left is Defense Under Secretary for Policy Michele Flournoy. (AP Photo)