[5] He was admitted to the state bar in 1913, when he was only 17, after the Arkansas General Assembly approved a special act waiving the normal age requirement for certification as a lawyer.

"[5] During his tenure in the House, he voted against President Franklin D. Roosevelt's court-packing plan, the Gavagan anti-lynching bill, and the Reorganization Act of 1937.

[citation needed] In 1942, after G. Lloyd Spencer decided not to seek re-election, McClellan, a self proclaimed racist, ran for the Senate again and this time won.

[citation needed] McClellan also served for eighteen years as chairman of the Senate Permanent Subcommittee on Investigations (1955–1973) and continued the hearings into subversive activities at the U.S. Army Signal Corps, Fort Monmouth, New Jersey, where Soviet spies Julius Rosenberg, Al Sarant and Joel Barr all worked in the 1940s.

[citation needed] In April 1961, during an Investigations subcommittee hearing, contractor Henry Gable asserted that Communists would not be able to do the same amount of damage to the American missile effort as done by labor at Cape Canaveral.

These hearings investigated the operations of organized crime and featured the testimony of Joseph Valachi, the first American mafia figure to testify about its criminal activities.

McClellan continued his efforts against organized crime (including backing the anti-organized-crime (RICO) law) until 1973, when he switched to investigating political subversion.

[citation needed] In 1957, McClellan opposed U.S. President Dwight D. Eisenhower's decision to send federal troops to enforce the desegregation of Central High School in Little Rock.

Prior to the sending of the troops under the command of Major General Edwin A. Walker, McClellan had expressed "regret [regarding] the ... use of force by the federal government to enforce integration.

"[8] McClellan and fellow Senator Robert S. Kerr of Oklahoma were the sponsors of the bill that authorized construction of the McClellan-Kerr Arkansas River Navigation System, maintained by the Army Corps of Engineers.

[9][10] McClellan's notable failure to find any legal wrongdoing led to his introduction of several pieces of new legislation including his own bill on October 12, 1965 setting new fiduciary standards for plan trustees.

[11] Senator Jacob K. Javits (R-NY) introduced bills in 1965 and 1967 increasing regulation on welfare and pension funds to limit the control of plan trustees and administrators.