

US Secretary of Defense Robert M. Gates speaks with village elders in the village of Tabin in Kandahar, Afghanistan, on March 8. US Navy Ensign Haraz N. Ghanbari/AP
CIA Director Leon Panetta speaks with reporters at CIA Headquarters in Langley, Va., in 2009. President Obama plans this week to name Mr. Panetta to replace Defense Secretary Robert Gates, and Gen. David Petraeus, now running the war in Afghanistan, would take the CIA chief's job in a major shuffle of the nation's top national security leadership. J. Scott Applewhite/AP/File
Chairman of the Joint Chiefs of Staff Admiral Mike Mullen holds a news conference in Baghdad, Iraq, on April 22. Saad Shalash/Reuters
Outgoing Press Secretary Robert Gibbs (r.) and incoming Press Secretary Jay Carney listen as President Obama speaks about Egypt and the resignation of President Hosni Mubarak in the Grand Foyer of the White House in Washington on Feb. 11. Charles Dharapak/AP/File
President Obama thanks outgoing White House Chief of Staff Rahm Emanuel as Emanuel's interim successor Pete Rouse looks on in the East Room at the White House in Washington in 2010. Emanuel was stepping down to run for mayor of Chicago, and won the election on Feb. 22. Jim Young/Reuters/File
US General David Petraeus, Commander of NATO International Security Assistance Force and US Forces in Afghanistan, addresses Royal United Service Institute members on 'The Mission in Afghanistan' in London on March 23. Sang Tan/AP
US Army General Stanley McChrystal, commander of the US Forces in Afghanistan, speaks to the media about Afghanistan from the James S. Brady Press Briefing Room at the White House in Washington in 2010. President Obama fired Mr. McChrystal as the top US and NATO commander in Afghanistan. Larry Downing/Reuters/File
President Obama announces that Commerce Sec. Gary Locke will be the next US ambassador to China in the Diplomatic Room of the White House in Washington on March 9. Locke is replacing Jon Huntsman. Pablo Martinez Monsivais/AP
Federal Reserve Chairman Ben Bernanke (l.) sits with Treasury Secretary Timothy Geithner before a meeting of the G-20 on April 15 at the World Bank/IMF Spring Meetings 2011 in Washington. Jacquelyn Martin/AP
From left, Vice President Joe Biden, Chief of Staff Bill Daley, and White House Press Secretary Jay Carney listen to President Obama speak at the White House in Washington regarding the budget and possible government shutdown on April 7. Pablo Martinez Monsivais/AP
White House senior advisers Valerie Jarrett and David Plouffe walk across the South Lawn of the White House in Washington on April 14 as they accompany President Obama to Chicago. Charles Dharapak/AP
Secretary of State Hillary Rodham Clinton gestures while speaking at the State Department in Washington on April 20. Alex Brandon/AP
Attorney General Eric Holder speaks about the Justice Department's priorities and mission at the Justice Department in Washington on April 25. Jacquelyn Martin/AP
Council of Economic Advisors Chairman Austan Goolsbee, President Obama's youngest cabinet member, speaks at the St. Regis Hotel in Washington on Feb. 24. Michael Bonfigli/The Christian Science Monitor