Video: 'ObamaWatch: Sen. Ervin's Opening Remarks, Chairman Senate Select Watergate Committee May 17 1973'

(Thursday, May 17, 1973, 10:02 a.m. EDT; during the Watergate scandal) — The United States Senate Watergate Committee, known officially as the Select Committee on Presidential Campaign Activities, a special committee established by the United States Senate to investigate the Watergate scandal, opened hearings today into a break-in at Democratic National headquarters in Washington.

The special committee was established with the power to investigate the June 17, 1972, break-in at the Democratic National Committee (DNC) headquarters at the Watergate office complex in Washington, D.C., and any subsequent cover-up of criminal activity, as well as “all other illegal, improper, or unethical conduct occurring during the controversial 1972 presidential election, including political espionage and campaign finance practices.”

Video: 'Vietnam: A Television History (Ep-12) The End of the Tunnel' (May 17, 1973, at 8:52)

Working under committee chairman Sam Ervin, the committee would play a pivotal role in gathering evidence that would lead to the indictment of forty administration officials and the conviction of several of President Richard Nixon’s aides for obstruction of justice and other crimes (click here to watch all 51 days of the hearings).

Its revelations later prompted the impeachment process against Nixon himself, which featured the introduction of three articles of impeachment by the Democratic-led House Committee on the Judiciary.

Video: 'PBS Nixon (1990)_3of3' (May 17, 1973, at 22:09)

Watergate led to Nixon’s resignation on August 9, 1974.

The first witness to testify was Robert C. Odle, Jr., a former official with the Committee to Re-Elect the President.

The first weeks of the committee’s hearings were a national political and cultural event. They were broadcast live during the day on commercial television; at the start, CBS, NBC, and ABC covered them simultaneously, and then later on a rotation basis, while PBS replayed the hearings at night.

Video: '"Watergate: The Secret Story" - 1992' (Senate Watergate Committee hearings at 1:03:49)

Some 319 hours were broadcast overall, and 85 percent of U.S. households watched some portion of them.

The audio feed also was broadcast, gavel-to-gavel, on scores of National Public Radio stations, making the hearings available to people in their cars and workplaces, and increasing the profile of the fledgling broadcast organization.

The hearings made stars out of both Ervin, who became known for his folksy manner and wisdom but resolute determination, and Baker, who appeared somewhat non-partisan and uttered the famous phrase “What did the President know, and when did he know it?” (often paraphrased by others in later scandals).