The seal of the CIA at the agency's headquarters in Virginia. Greg E. Mathieson Sr. /MAI/Landov hide caption

itoggle caption Greg E. Mathieson Sr. /MAI/Landov

A Free Syrian Army fighter looks through the scope of his sniper rifle at an area controlled by forces loyal to President Bashar Assad in Aleppo. Reuters/Landov hide caption

itoggle caption Reuters/Landov

Don't go there: A warning sign marks the boundary of Area 51 in Nevada. Dan Callister/Getty Images hide caption

itoggle caption Dan Callister/Getty Images

The seal of the Central Intelligence Agency. The case that prosecutors want journalist James Risen to testify in involves an alleged leak of information by a former CIA agent. Greg E. Mathieson Sr. /MAI/Landov hide caption

itoggle caption Greg E. Mathieson Sr. /MAI/Landov

In Moscow's Red Square, people still line up to visit Lenin's tomb. Though the Cold War is over, Russia and the U.S. keep watchful eyes on each other. Tuesday, Russian officials claimed to have uncovered a CIA spy. Sergei Ilnitsky /EPA /Landov hide caption

itoggle caption Sergei Ilnitsky /EPA /Landov

Former CIA director and retired Gen. David Petraeus during his address Tuesday at the University of Southern California. Frederic J. Brown /AFP/Getty Images hide caption

itoggle caption Frederic J. Brown /AFP/Getty Images

The nominees: John Brennan (left), who is President Obama's choice to head the CIA; and former Sen. Chuck Hagel, R-Neb., who the president has asked to be secretary of defense. STAFF/Reuters /Landov hide caption

itoggle caption STAFF/Reuters /Landov

John Brennan, who President Obama wants to lead the CIA. Alex Wong/Getty Images hide caption

itoggle caption Alex Wong/Getty Images

Then-CIA Director David Petraeus testifies on worldwide threats before the Senate Select Committee on Intelligence, on Jan. 31. Zhang Jun/Xinhua /Landov hide caption

itoggle caption Zhang Jun/Xinhua /Landov

David Petraeus, while he was the top commander of U.S. and coalition forces in Afghanistan, and Paula Broadwell in July 2011. He resigned from his post as CIA director because of an extramarital affair they had. ISAF/Reuters /Landov hide caption

itoggle caption ISAF/Reuters /Landov