Once a bastion of conservative anti-communism under long-time director J. Edgar Hoover, the FBI has become one of the more liberal political agencies of government, and some critics say appears increasingly to operate outside normal constitutional controls.
The shift is the result of a bureaucratic culture that emerged in the 1990s and was fueled by its two most recent former directors, James Comey and Robert Mueller, who ran the agency for the past 16 years. Mueller headed the FBI from 2001 to 2013, when Comey took over and served until he was fired by Trump in May.
Both former directors currently are at the center of a fierce political debate over the FBI's competency and integrity.