Douglas M. Charles reveals how FBI Director J. Edgar Hoover catered to President Franklin D. Roosevelt's political interests. Between 1939 and 1945, the Federal Bureau of Investigation monitored the political activities of President Roosevelt's anti-interventionist foreign policy critics. Hoover, whose position as FBI director was tenuous within the left-of-center Roosevelt administration, catered to the president's political and policy interests in order to preserve his position and to expand FBI authority.