The Senate Watergate Committee formally subpoenaed tapes and documents from President Nixon on July 23, 1973, following revelations by aide Alexander Butterfield that Nixon had secretly recorded Oval Office conversations. Nixon refused, citing executive privilege, triggering a year-long legal and political battle over the tapes that ultimately produced evidence of obstruction of justice and forced his resignation in August 1974.
The Watergate scandal had simmered for over a year following the June 1972 break-in at the Democratic National Committee headquarters, but it lacked a smoking gun until testimony that week. On July 16, 1973, White House aide Alexander Butterfield revealed under questioning that Nixon had installed a voice-activated taping system throughout the Oval Office, capturing years of private conversations.
The revelation transformed the investigation overnight. If tapes existed, they could either exonerate or doom the president depending on what they revealed about his knowledge of the break-in and subsequent cover-up. On July 23, 1973, the Senate Select Committee on Presidential Campaign Activities, chaired by Senator Sam Ervin, issued a subpoena demanding Nixon produce specific recordings. Special prosecutor Archibald Cox issued a parallel demand.
Nixon refused, arguing that executive privilege and national security required confidentiality of presidential deliberations, setting off a constitutional confrontation that would grind through courts for over a year. The fight culminated in the Supreme Court's unanimous 1974 ruling in United States v. Nixon, forcing release of the tapes, including the damning June 23, 1972 recording in which Nixon discussed the cover-up. Nixon resigned weeks later, the only American president to do so.