By Steve Gorman
LOS ANGELES (Reuters) - The U.S. National Archives released on Wednesday its last installment of White House conversations that were secretly recorded by President Richard Nixon in the 1970s, a batch of tapes mainly highlighting domestic and foreign policy issues.
The 340 hours of conversations cover a three-month period from April 9 to July 12, 1973, the day before the existence of Nixon's taping system was revealed by presidential aide Alexander Butterfield in testimony before a U.S. Senate Select Committee investigating the Watergate scandal.
Nixon resigned from office about a year later, in August 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, administered by the National Archives in Nixon's birthplace of Yorba Linda, California, 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 library said in a statement.
The voice-activated system also captured the 1973 Oval Office meeting between Nixon and Brezhnev, the only summit-level meeting ever recorded by a U.S. 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, including tapes used as evidence in various Watergate-related trials or by special investigators with the prosecutor's office, was released in four previous batches between May 1980 and November 1996, according to the National Archives.
The non-Watergate material has been made available to the public after years of litigation, under a settlement among the National Archives, Nixon's estate and Stanley Kutler, a historian who sued to win release of the tapes.
Nixon's taping system, known only to a few aides before it was disclosed, extended not only to the Oval Office but also to the White House Cabinet Room, the Lincoln Sitting Room in the mansion's living quarters, Nixon's office at the Executive Office Building next door and the presidential retreat at Camp David in Maryland.
Nixon was not the first president to secretly record his White House conversations. A certain amount of taping was done by each of his predecessors going back to Franklin Roosevelt.
(Editing by Cynthia Johnston and Matthew Lewis)