The 340 hours of conversations cover a three-month period from Apr 9 to Jul 12, 1973, the day before the existence of Nixon’s taping system was revealed by presidential aide Alexander Butterfield in testimony before a US senate select committee investigating the Watergate scandal.
Nixon resigned from office about a year later, in Aug 1974, facing almost certain impeachment over the involvement of his staff and campaign team in an attempt to bug his Democratic opponents’ offices at the Watergate complex and their efforts to cover it up.
By then, the White House taping system, installed by Nixon in 1971, had been dismantled, apparently on the orders of either Nixon himself or his then-chief of staff, Alexander Haig.
But never-before-heard material from the latest batch of 94 tapes made available through the Richard Nixon Presidential Library and Museum, deals mostly with subjects other than Watergate.
They include conversations related to such Cold War-era events as the Vietnam peace settlement and the return of prisoners of war, as well as the aftermath of the 1972 superpower summit between Nixon and Soviet leader Leonid Brezhnev.
The voice-activated system also captured the 1973 Oval Office meeting between Nixon and Brezhnev, the only summit-level meeting ever recorded by a US presidential taping network.
Among the range of domestic-policy subjects are conversations about wage and price controls, energy policy, campaign finance reform, and the Native American uprising at Wounded Knee, South Dakota.
Archive officials say that any newly disclosed mentions of Watergate are confined to conversations deemed not to involve government abuses of power, such as discussions of press coverage of the scandal and how it was affecting White House scheduling.
The bulk of Watergate material was released in four batches between May 1980 and Nov 1996.