Robert Mueller

Age: 72; born in New York

Education: Princeton University, University of Virginia, New York University, University of Virginia School of Law.

Job history: Worked at the U.S. attorney's office in San Francisco, Boston and District of Columbia before becoming interim U.S. attorney in 1998 and then later confirmed as U.S. attorney. Director of FBI from 2001 to 2013, a tenure second in length only to FBI founder J. Edgar Hoover.

Key cases: Worked on the investigation into the 1988 bombing of Pan Am Flight 103 over Lockerbie, Scotland; in charge of the initial investigation into the Boston Marathon bombings; after he left the FBI, managed litigations against Volkswagen and the dispersal of restitution in Takata airbags.

Mueller, Comey have history

In a high-drama episode in 2004, then-FBI Director Robert Mueller and then-Deputy Attorney General James Comey were involved in a standoff with other George W. Bush administration officials over an effort to extend the National Security Agency's warrantless wiretapping program.

Comey had been notified that White House Counsel Alberto Gonzales and Chief of Staff Andrew Card were on their way to the hospital to persuade Attorney General John Ashcroft — who was in intensive care after gall bladder surgery— to reauthorize Bush's domestic surveillance program, which the Justice Department had just determined was illegal.

Comey alerted Mueller and raced, sirens blaring, to join Ashcroft in his hospital room to persuade him not to certify the extension sought by Gonzales and Card, who arrived minutes after Comey.

Ashcroft, summoning the strength to lift his head and speak, refused to sign the papers Gonzales and Card had brought. They left the room without ever acknowledging Comey's presence.

Mueller arrived at the hospital shortly after the confrontation in Ashcroft's room. He told the FBI agents guarding the door not to allow anyone else in to see Ashcroft without Comey's permission.

When the Bush administration tried to proceed with the extension, Comey, Mueller, Ashcroft and other Justice Department officials threatened to resign — forcing Bush to change the program.

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