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A History of Notable Senate Investigations

Chapter 1: Origins
Chapter 2: Process
Chapter 3: Challenges
Chapter 4: Senate Investigations: A Selected List


The authority of Congress to investigate is an implied constitutional power. James Madison anticipated the significance of congressional inquiry in Federalist 51 when he urged: "In framing a government which is to be administered by men over men. . .you must first enable the government to control the governed; and in the next place oblige it to control itself." Congress has exercised its investigative responsibility since the earliest days of the republic. Today congressional oversight enables House and Senate members to serve as the eyes and ears of the American public.

Congressional investigations date back to 1792 when the House passed a resolution to examine the disastrous St. Clair expedition. Since then Congress has conducted hundreds of investigations. Noteworthy inquiries have required a combination of persistence, thoroughness, expert staff, sharp questioning, good publicity, and some luck. Successful investigators diligently conduct background research and have been shrewd in evaluating evidence and in questioning witnesses. The very best have managed to achieve a level of bipartisanship to maintain credibility. Particularly during the second half of the 20th century, senators and their committee staff have honed their public relations skills to attract press coverage and hold public attention. Historically significant Senate investigations have uncovered wrongdoing, have punished transgressors, and have produced legislation aimed at prohibiting similar abuse in the future.

Congressional investigations have not been confined to oversight of the executive or judicial branches though that has often been the focus of past inquiries. Congress may investigate anything related to the development of public policy. Since its earliest investigations, Congress has availed itself of the power of inquiry in order to inform the public and to write good legislation. Over the past two centuries the Senate has probed issues such as interstate commerce, Ku Klux Klan activities, the sinking of the R.M.S. Titanic , Wall Street banking practices, organized crime, antiunion activity, the sale of cotton, and the Vietnam War. Perhaps the Senate's best-known investigatory committee, the Select Committee on Presidential Campaign Activities (commonly known as the Watergate Committee), investigated alleged malfeasance in the executive branch and was instrumental in bringing about the resignation of President Richard Nixon.


Each house of Congress governs its committee investigations through authorizing or enabling resolutions, which define the scope of the inquiry and identify the anticipated result. Many investigations are performed by select or special committees, established to probe a particular issue, report on it, and make policy recommendations based on that report. Committee members may inquire into those issues that are relevant to the subject under investigation. In the case of temporary committees, members generally set their own procedural rules based on the majority vote of committee members.

In 1827, the House empowered the Committee on Manufactures "to send for persons and papers" relating to tariff legislation, and since then both houses have considered it their right to summon anyone, whether inside or outside the government, to testify. In 1857, Congress provided that reluctant witnesses could be held in contempt and tried by federal courts. The Senate passed a resolution to conduct its first legislative inquiry on December 14, 1859, creating the Select Committee to Inquire into the Facts of the Recent Invasion and Seizure of the United States Armory at Harper's Ferry. Since then, the Senate has increasingly recognized the importance of investigations, and has expanded its powers to conduct inquiries including subpoena power for all standing committees granted by the Legislative Reorganization Act of 1946.


Two processes have threatened Congress' investigatory power: the executive branch's refusal to cooperate with inquiries and the perception that committees have overstepped their constitutional authority. In 1881 the Supreme Court decided, in Kilbourn v. Thompson, that a House investigation into the bankruptcy of Jay Cooke and Company had exceeded its authority because no clear legislation could result from the inquiry. Generally, however, the courts have broadly construed congressional powers to conduct investigations. During the Senate investigation of the Teapot Dome scandal in the 1920s the Supreme Court held in McGrain v. Daugherty (1927), that congressional committees could issue subpoenas, could compel witnesses to testify, and could hold them in contempt if they failed to comply. In a second decision, Sinclair v. United States (1929), the Court ruled that a witness who lies before a congressional committee can be convicted of perjury.

Investigations, in the words of Senator Sam Ervin, chairman of the Watergate Committee, "can be the catalyst that spurs Congress and the public to support vital reforms in our nation's laws." He cautioned, however, that probes may also "afford a platform for demagogues and the rankest partisans." Despite these challenges, investigations remain a critical tool for legislators to formulate laws and inform public opinion.

Senate Investigations: A Selected List

1859-1860 Select Committee to Inquire into the Facts of the Recent Invasion and Seizure of the United States Armory at Harper's Ferry   (The Harper's Ferry Inquiry)

Resolution passed: December 15, 1859. Report: June 15, 1860.

Chairman: James Murray Mason (D-VA)

Investigation of John Brown's raid on the arsenal at Harper's Ferry, Virginia.

1861-1865 Joint Committee on the Conduct of the War

Resolution passed: December 10, 1861. Report: May 22, 1865.

Chairman: Senator Benjamin Wade (R-OH)

Investigation of the executive branch's conduct of the Civil War.

1871-1873 Select Committee to Investigate Alleged Outrages in the Southern States

Resolution passed: January 19, 1871. Terminated: March 12, 1873.

Chairman: John Scott (R-PA)

Investigation of Ku Klux Klan activities in North Carolina.

1885-1886 Select Committee to Investigate Interstate Commerce

Resolution passed: March 17, 1885. Report: January 18, 1886.

Chairman: Shelby Cullom (R-IL)

Investigation of railroad and water interstate transportation regulation; led to 1887 passage of Interstate Commerce Act.

1912 Senate Committee on Commerce, Subcommittee Hearings   (Titanic Disaster Investigation)

Hearings: April 18, 19, 22, 1912. Report: May 28, 1912.

Chairman: William Alden Smith (R-MI)

Investigation of the sinking of the H.M.S. Titanic.

1912 Committee on Privileges and Elections, Subcommittee Hearings   (The Clapp Committee)

Resolution passed: April 27, 1912. Hearings: June, October 1912.

Chairman: Moses E. Clapp (R-MN)

Investigation of campaign contributions during the presidential elections of 1904 and 1908.

1913-1917 Senate Committee on the Judiciary Special Lobby Investigation

Hearings: June to September 1913, January to July 1914. Report July 16. 1917.

Chairman: Charles A. Culberson (D-TX)

Investigation of alleged lobbying activities in Washington, D.C., and elsewhere.

1923-1924 Committee on Public Lands and Surveys   (The Teapot Dome Investigation)

Hearings: October 22, 1923 to May 14, 1924. Report: June 6, 1924.

Chairman: Thomas J. Walsh (D-MT)

Investigation of government oil reserves in Wyoming leased to oilmen and developers.

1932-1934 Committee on Banking and Currency Investigation of Wall Street   (The Pecora Wall Street Expose)

Hearings: April 11, 1932 to May 4, 1934.

Chairman: Peter Norbeck (R-SD), 1932-1933; Duncan U. Fletcher (D-FL), 1933-1936

Investigation of Wall Street banking and stock exchange practices; led to passage of the Securities Act of 1933, the Banking Act of 1933, and the Securities Exchange Act of 1934.

1933 Special Committee to Investigate Air Mail and Ocean Mail Contracts

Resolution passed: February 25, 1933. Terminated: June 30, 1936.

Chairman: Hugo Black (D-AL)

Investigation into use of government mail subsidies; led to passage of Air Mail Act of 1933.

1934-1936 Special Committee Investigating the Munitions Industry   (The Nye Munitions Committee)

Hearings: September 1934 to February 1936.

Chairman: Gerald R. Nye (R-ND)

Investigation of the manufacturing and sale of munitions and the economic circumstances of U.S. entry into World War I.

1935-1938 Special Committee to Investigate Lobbying Activities   (Public Utility Companies Investigation)

Resolution passed: July 11, 1935. Terminated: June 16, 1938.

Chairman: Hugo Black (D-AL), 1935-1937; Sherman Minton (D-IN), 1937-1938

Investigation of public utility company lobbyists.

1936-1940 Education and Labor Committee, Subcommittee on Civil Liberties   (Senate Civil Liberties Committee)

Hearings: April 10, 1936 to July 1, 1940.

Chairman: Robert M. La Follette, Jr. (R-WI)

Investigation of antiunion practices.

1941-1948 Special Committee to Investigate the National Defense Program   (The Truman Committee)

Resolution passed: March 1, 1941. Last hearing: November 22, 1948.

Chairman: Harry S. Truman (D-MO), 1941-1945; James M. Mead (D-NY), 1945-1947; Owen Brewster (R-ME), 1947-1948

Investigation of defense contracts.

1945-1946 Joint Committee on the Investigation of the Pearl Harbor Attack   (Pearl Harbor Committee)

Hearings: November 1945 to May 1946.

Chairman: Alben Barkley (D-KY)

Investigation of the attack at Pearl Harbor.

1949 Committee on Expenditures in the Executive Departments, Investigations Subcommittee   ("Five Percenters" Investigation)

Hearings: August 8 to 26, 1949. Report: January 18, 1950.

Chairman: Clyde R. Hoey (D-NC)

Investigation of influence peddling in defense contracts.

1950 Foreign Relations Committee Subcommittee Investigation of Charges by Senator McCarthy   (The Tydings Committee)

Hearings: March 8 to June 28, 1950. Report: July 20, 1950.

Chairman: Millard E. Tydings (D-MD)

Investigation of alleged disloyalty by State Department employees.

1950-1951 Special Committee to Investigate Organized Crime in Interstate Commerce   (The Kefauver Committee)

Resolution passed: May 3, 1950. Report: August 31, 1951.

Chairman: Estes Kefauver (D-TN), 1950-1951; Herbert R. O'Conor (D-MD), 1951

An investigation of organized crime in America. Many of the hearings were broadcast nationally on television.

1951 Committee on Armed Services and the Committee on Foreign Relations Inquiry into MacArthur Dismissal   (The MacArthur Inquiry)

Hearings: May 3 to June 27, 1951.

Chairman: Richard Russell (D-GA)

Investigation of the dismissal of General of the Army Douglas MacArthur and of U.S. policy in the Far East.

1953-1954 Senate Committee on Government Operations, Permanent Subcommittee on Investigations   (The McCarthy Hearings) and (The Army-McCarthy Hearings)

The investigations by this subcommittee can be divided into two distinct phases. The first consisted of a series of hearings conducted by Joseph McCarthy throughout 1953 regarding alleged Communist influence on the press and on government, including "The Voice of America," the State Department's overseas information centers, and the U.S. Army.

Report: January 25, 1954.

Chairman: Joseph R. McCarthy (R-WI)

The second phase involved the committee's investigation of Senator McCarthy's attacks on the army. These hearings were broadcast on national television.

Hearings: April 22 to June 17, 1954. Report: August 31, 1954.

Acting Chairman: Karl E. Mundt (R-SD)

1957-1960 Select Committee on Improper Activities in Labor-Management Relations   (Labor Racketeering Investigation)

Resolution passed: January 30, 1957. Report: March 31, 1960.

Chairman: John L. McClellan (D-AR)

Investigation into corruption in the labor or management field, including in the Teamsters union. The committee heard from more than 1,500 witnesses over 270 days of hearings.

1964 Rules and Administration Committee   (Bobby Baker Case)

Hearings: October and December 1963; February, October, December, 1964. Report: July 8, 1964.

Chairman: B. Everett Jordan (D-NC)

Investigation of conflicts of interest and financial improprieties engaged in by Baker, who served as secretary to the majority until he resigned on October 7, 1963.

1973-1974 Select Committee on Presidential Campaign Activities   (The Watergate Committee)

Resolution passed: February 7, 1973. Report: June 27, 1974.

Chairman: Samuel Ervin (D-NC)

Investigation of possible corruption in the 1972 presidential election campaign.

1975 Select Committee to Study Governmental Operations with Respect to Intelligence Activities   (Church Committee)

Resolution passed: January 27, 1975. Report: April 29, 1976.

Chairman: Frank F. Church (D-ID)

Investigation into abuse of power in intelligence-gathering by CIA and the FBI.

1987-1989 Select Committee on Secret Military Assistance to Iran and the Nicaraguan Opposition  
(Iran-Contra Hearings)

Hearings: May 5 to August 3, 1987. Report: November 17, 1987.

Chairman: Daniel Inouye (D-HI)

Investigation into alleged covert sales of military equipment to Iran and diversion of the proceeds to aid the Nicaraguan Contras.

Senate Investigations: A Selected List