John Dean III, former White House aide in the Nixon Administration, adjusts his eyeglasses as he nears the end of reading his 245-page prepared statement before the Senate Watergate Committee in Washington, D.C., on June 25, 1973. In his seven-hour opening statement Dean said that the president was involved in the cover-up of the Watergate burglary. (AP Photo)

** FILE ** Former White House aide John Dean III is sworn in by Senate Watergate Committee Chairman Sam Ervin, D-N.C. in this June 25, 1973 file photo. It has been the stage for Washington's grandest political theater: the investigation of the sinking of the Titanic, the Army-McCarthy hearings, and presidential scandals from Teapot Dome to Watergate and Iran-Contra. When John Roberts takes the oath in the Caucus Room of the Senate's Russell office building, he will join nearly a century's worth of witnesses to undergo the scrutiny of senators there. (AP Photo/File)

Former white house counsel John W. Dean, accompained by his wife, Maureen leaves U.S.. district court in Washington Tuesday, June 12, 1973. Earlier in the day U.S. district judge John J. Sirica granted Dean use immunity, meaning that any testimony he gives before Senate Watergate committee cannot be used to develop a case against him. Dean's attorney declined any comment on what transpired inside the court. (AP Photo/Harvey Georges)

This is a photo of convicted Watergate conspirator E. Howard Hunt taken on June 11, 1973 in Washington D.C. (AP Photo)

Former FBI agent Alfred Baldwin delivers testimony May 25, 1973 on Capitol Hill to members of the Watergate committee. (AP Photo)

Former agent of the Federal Bureau of Investigation, Alfred C. Baldwin is shown testifying May 24, 1973 in hearing by the Senate Select Committee of the Watergate case. (AP Photo/Bob Daugherty)

Sen. Daniel K. Inouye (D-Hawaii), a member of the Watergate investigating committee, questions witness James McCord during the hearing on Capitol Hill, May 19, 1973. At right is John M. Montoya, Democrat of New Mexico. (AP Photo)

Sen. Daniel K. Inouye (D-Hawaii), a member of the Watergate investigating committee, questions witness James McCord during the hearing on Capitol Hill, May 19, 1973. At right is John M. Montoya, Democrat of New Mexico. (AP Photo)

Archibald Cox of Harvard Law school speaks during a news conference at Harvard in Cambridge, Mass., May 18, 1973, after he was named prosecutor in the Watergate case. (AP Photo/J. Walter Green)

Senator Sam Ervin, D-N.C., chairman of the Watergate Investigating Committee, listens to other members of the committee Thursday May 18, 1973 during the first day of public hearings in Washington. They are, from left; Fred Thompson, chief minority couns. Sen. Howard Baker, R-Tenn., Ervin; and Samuel Dash, Chief majority. (AP Photo).

Hearings of the Senate select committee on the watergate case in Washington, D.C. May 18,1973. (AP Photo)

Senator Sam Ervin, Jr. Chairman of hearings of the Senate select committee on the watergate case in Washington, D.C. May 18,1973. (AP Photo)

Senator Sam Ervin, Jr. Chairman of hearings of the Senate select committee on the watergate case in Washington, D.C. May 18,1973. (AP Photo)

Sen. Daniel K. Inouye (D-Hawaii), a member of the Senate Watergate investigating committee, is shown, May 18, 1973. (AP Photo)

WASHINGTON, May 17, 1973- Members of the Senate Watergate Investigating committee in Washington, D.C., May 17, 1973, From left are; Sen. Lowell Weicker, R-Conn., Sen. Edward Gurney, R-Fla., Chief Minority Counsel Fred Thompson, Sen. Howard Baker, R-Tenn., Sen. Sam Ervin, D-N.C., Chairman, Chief counsel Samuel Dash, Sen, Herman Talmadge, D-Ga., Sen. Daniel Inouye, D-Hawaii and Sen. Joseph Montoya, D-N. Mexico. In foreground is witness Robert Odle. (AP Photo).

Sen. Fred D. Thompson, Chief Minority Counsel of the Senate Watergate Committee, is seen with Sen. Howard Baker (R-Tenn.), during the Watergate hearings in Washington, May 17, 1973. (AP Photo)

Yale Political Union President Wade Cleveland whispers an aside to R. Sargent Shriver before introducing him at a public meeting of the Yale Political Union, Thursday, May 17, 1973 in New Haven. Shriver, who was the speaker of the evening, said that President Nixon should be prepared to choose any ??sdecent alternative that can repair the damage??? of the Watergate scandal. (AP Photo/Bob Child)

Sen. Howard Baker (R-Tenn.), right, confers with minority counselor for the Senate Watergate Committee Fred Thompson, on the steps of the Capitol, May 16, 1973. (AP Photo)

Frank Wills, the security guard who discovered the now infamous Watergate break-in on June 17, is now working as a security guard in another Washington office building shown May 16, 1973. It was Wills chance discovery of a piece of tape attached to a Watergate Basement door latch that lead to the arrest of five men in connection with the breaking into of the democratic national committee offices. (AP Photo)

Former CIA director Richard Helms appears in Washington, before closed hearing of the Senate Appropriations Subcommittee that is investigating government intelligence operations, May 16, 1973. Helms headed the intelligence unit at the time of the break-in at the Democratic Nation Committee headquarters in the Watergate complex. (AP Photo/Henry Griffin)