H.R. Haldeman, former White House domestic affairs advisor, charged in the Watergate cover-up is shown outside U.S. District Court in Washington, March 9, 1974 where he faces arraignment. (AP Photo)

This artist rendering shows the scene in U.S. District Court Saturday, March 9, 1974 when Judge John J. Sirica, foreground, faced the seven men being arraigned on charges stemming from their allegd involvement in the Watergate affair. They are, from left: John D. Ehrlichman, former presidential aid; H.R. Haldman, former White House chief staff; Godon C. Strachan, former aide to Haldeman; Kenneth W. Parkinson, a lawyer retained by the committee to re-elect the president; Charles W. Colson, former special White House counsel; former Attorney Gen. John N. Mitchell; and Robert C. Marcian, former head of internal security at the Justice Department. The drawing is courtesy of ABC artist Frieda Reiter. (AP Photo)

John D. Ehrlichman, President Nixon's former top domestic advisor, walks to U.S. District Court in West Washington on Saturday, March 9, 1974. Ehrlichman entered a plea of innocent to charges that he was involved in the Watergate cover-up. (AP Photo)

John D. Ehrlichman, President Nixon's former top domestic advisor, walks to U.S. District Court in West Washington on Saturday, March 9, 1974. Ehrlichman entered a plea of innocent to charges that he was involved in the Watergate cover-up. (AP Photo)

Six persons charged in the Watergate cover-up are shown outside U.S. district court on Saturday, March 9, 1974 in Washington where they faced assignment. Top row, from left, John B. Ehrlichman, former White House domestic affairs advisor.(AP Photo)

H.R. Haldeman, tanned and sporting his new longer hairstyle, tells a news conference on the front lawn of his home in Los Angeles March 4, 1974, that he is innocent of all Watergate cover-up charges. Haldeman said he is confident he will be cleared of conspiracy, obstruction of justice and perjury charges. (AP Photo/Jeff Robbins)

H.R. Haldeman, smiling and tanned and sporting his new longer hairstyle, tells a news conference on the front lawn of his home in Los Angeles March 4, 1974, that he is innocent of all Watergate cover-up charges. Haldeman said he is confident he will be cleared of conspiracy, obstruction of justice and perjury charges. (AP Photo/Jeff Robbins)

Tanned and smiling, H. R. Haldeman tells an outdoor news conference at his Los Angeles home March 4, 1974 that he is confident that he'll be vindicated of charges of conspiracy and perjury in the Watergate cover-up. The former White House aide said he is proud of having served in the Nixon administration. (AP Photo/Jeff Robbins)

H.R. Haldeman talks briefly to newsmen at the door of his home, March 1, 1974, after learning a grand jury in Washington, D.C., had indicted him and six others on charges of conspiracy to obstruct Watergate investigations. The former top White House aide was charged with three counts of perjury and one of conspiracy to obstruct justice. (AP Photo/George Brich)

H.R. Haldeman, once a top Presidential advisor, is alternately somber and laughing as he poses briefly at the door of his Los Angeles home, March 1, 1974, shortly after a federal grand jury Washington indicted him and six others on charge of conspiring and lying to block the Watergate investigations. (AP Photo/George Birch)

Former White House attorney Charles Colson faces reporters after he was charged in the Watergate cover-up, March 1, 1974. (AP Photo/Charles Bennett)

H.R. Haldeman, once a top Presidential advisor, is alternately somber and laughing as he poses briefly at the door of his Los Angeles home, March 1, 1974, shortly after a federal grand jury Washington indicted him and six others on charge of conspiring and lying to block the Watergate investigations. (AP Photo/George Birch)

Assistant Special Watergate Prosecutor Jill Volner leaves U.S. District Court in Washington on Friday, March 1, 1974, after a federal grand jury handed down indictments charging seven people with involvement in the Watergate cover up. U.S. District Judge John J. Sirica scheduled arraignments on those charged for March 9. (AP Photo)

Assistant Watergate prosecutors Richard Ben-Veniste and Jill Vollner, right, talk with newsmen after U.S. District Judge John J. Sirica said he will recommend the case of the 18?? minute gap in a White House tape to the grand jury for action on Friday, Jan. 18, 1974 in Washington. (AP Photo)

FILE--Vice President Gerald Ford says the White House is willing to negotiate with the Senate Watergate committee on releasing some of the tapes and documents demanded by that panel in a Washington interview in this January 11, 1974 file photo. Gerald R. Ford, who picked up the pieces of Richard Nixon's scandal-shattered White House as the 38th and only unelected president in America's history, has died, his wife, Betty, said Tuesday Dec. 26, 2006. He was 93. (AP Photo/Charles Gorry, File)

Attorney General William B. Saxbe, right, smiles as he talks with Special Watergate Prosecutor Leon Jaworski, left, and Federal Bureau of Investigation Director Clarence M. Kelley in Washington on Friday, Jan. 5, 1974. The men are pictured here in the Great Hall of the Justice Department immediately after Saxbe was sworn in. (AP Photo/Henry Burroughs

Atty. Gen. designate William Saxbe, left, and special Watergate prosecutor Leon Jaworski exchange comments during a break in Saxbe???s confirmation hearing at Capitol Hill on Wednesday, Dec. 13, 1973 in Washington before the Senate Judiciary Committee. (AP Photo)

Attorney General designate William Saxbe, left, and special Watergate prosecutor Leon Jaworski exchange comments during a break in Saxbe???s confirmation hearing at Capitol Hill on Wednesday, Dec. 13, 1973 in Washington before the Senate Judiciary Committee. (AP Photo)

Jill Volner and Richard Ben-Veniste, assistant Watergate prosecutors, leave United States District Court in Washington on Friday, Nov. 30, 1973. They are walking toward a waiting car. (AP Photo)

Assistant Watergate prosecutors Jill Volner, right, and Richard Ben-Veniste arrive at U.S. District Court in Washington on Wednesday, Nov. 28, 1973 in a light rain for another round of testimony concerned with the presidential tapes. Tuesday Miss Volner visited the office of President Nixon's personal secretary, Rose Mary Woods, to check on where Miss Woods keeps things. (AP Photo)