WASHINGTON -- One of the abiding mysteries in the scandal that brought down President Richard M. Nixon is how part of a crucial Watergate tape came to be erased before the White House relinquished it to federal prosecutors.
The erasure, popularly known as the 18 1/2 -minute gap, was admitted by Rose Mary Woods, Mr. Nixon's personal secretary and confidante, who insisted in 1973 court testimony that it was accidental. Miss Woods said she had depressed a foot pedal for several minutes inadvertently while talking to a friend on the telephone -- an explanation prosecutors regarded as & 2/3 preposterous but could never disprove.
Now a new document from Miss Woods' personal files, released yesterday by the National Archives among 270,000 additional pages of Nixon materials, suggests that the erasure was deliberate. But the document itself seems almost as mysterious as the gap.
Dated Jan. 10, 1974, but unsigned, the typewritten document with no letterhead reports that Nixon White House lawyers Leonard Garment and J. Fred Buzhardt told two months earlier of "their client Miss Woods intentionally, not accidentally, erasing 18 1/4 minutes of the June 20, 1972, tape" of a conversation about the Watergate break-in between Mr. Nixon and his chief of staff, H. R. Haldeman.
The 13-page memo, headed "Memorandum to Research Staff," said Mr. Garment and Mr. Buzhardt also advised Watergate prosecutor Leon Jaworski and U.S. District Judge John J. Sirica, who subsequently conducted a hearing on the erasure, that "there is no innocent explanation of the gap or erasure." The two lawyers implied that Miss Woods might be guilty of obstruction of justice -- since the tape was under subpoena -- and they arranged for her to be represented by an outside attorney, the memo said.
Karl Weissenbach, a deputy archivist who has helped organize the Nixon files, said he does not know who wrote the memo. "We're not entirely sure it is a White House document," he said, although it was found among Miss Woods' files.
Mr. Garment, now a Washington attorney, said he recalled telling Mr. Jaworski and Judge Sirica -- both of whom are dead -- that he believed there was "no clear-cut innocent explanation" for the erasure, which Miss Woods said occurred while she was transcribing the White House recording.
Mr. Garment said he and Mr. Buzhardt, who also has died, avoided questioning Miss Woods directly because they did not think they could properly represent her interests while continuing to represent Mr. Nixon's. But after she retained Charles Rhyne as her private attorney, Mr. Garment said, he came to accept Miss Woods' sworn testimony in court that the erasure was accidental or was the result of a mechanical malfunction. Neither Mr. Rhyne nor Miss Woods could be reached for comment.
Richard Ben-Veniste, an associate Watergate prosecutor who questioned Miss Woods in open court, said the new memo only strengthens his conviction that the erasure was deliberate.
If that could have been proven, he said, Miss Woods or other White House aides would have been indicted for obstruction of justice.