Frank H. Strickler, a longtime Washington lawyer who defended two of President Richard M. Nixon’s top aides, H.R. Haldeman and John Ehrlichman, during the Watergate trials of the 1970s, died March 29 at his home in Chevy Chase. He was 92.

He had heart disease, his daughter Betsy Strickler said.

Mr. Strickler, a onetime federal prosecutor, joined one of his law partners, John J. Wilson, in defending two of the highest-ranking figures implicated in the Watergate scandal. Halde man was Nixon’s chief of staff, and Ehrlichman was a presidential counsel and adviser for domestic affairs.

The wide-ranging Watergate investigation began after five men were arrested for breaking into the Democratic national headquarters at the Watergate office complex on June 17, 1972.

Haldeman and Ehrlichman stoutly denied any connection to the Watergate burglary, and Mr. Strickler and Wilson sought to have the charges quashed. As the investigation led by special prosecutors Archibald Cox and, later, Leon Jaworski, moved forward, Haldeman and Ehrlichman resigned their White House posts in April 1973.

Frank H. Strickler, seen here in 1974, was an attorney for H.R. Haldeman and John Ehrlichman, two top aides of President Richard M. Nixon who were convicted of conspiracy and obstruction of justice during the Watergate scandal of the 1970s. (Harry Naltchayan/THE WASHINGTON POST)

In February 1974, after consulting Mr. Strickler and Wilson, Ehrlichman rejected an offer from Jaworksi to plead guilty to a single charge of conspiracy in return for testimony against other Watergate defendants.

“It was certainly Mr. Ehrlichman’s feeling that he was not guilty of anything,” Mr. Strickler said at the time. “He wasn’t going to plead guilty just to satisfy another cause.”

Ehrlichman ultimately hired other lawyers and was convicted of conspiracy and obstruction of justice. Mr. Strickler and Wilson continued to represent Haldeman through his trial in late 1974.

“Watergate was one of the most gigantic, stupid pieces of idiot action this country has ever seen,” Mr. Strickler said in court while arguing for Haldeman’s innocence. He said Haldeman had too many responsibilities in the White House to be involved in Watergate.

“The Watergate matter,” he said, “was no more than pimple on the mound of his other duties.”

Haldeman was found guilty of conspiracy and obstruction of justice. Both he and Ehrlichman served 18 months in federal prison.

Frank Hunter Strickler was born Jan. 20, 1920, in Washington and was a 1938 graduate of the old Central High School. He worked as an examiner for the FBI while attending George Washington University, from which he received a bachelor’s degree in political science in 1942. He served in the merchant marine during World War II and received a law degree from GWU in 1947.

Mr. Strickler was a law clerk for U.S. District Judge Bolitha J. Laws and an assistant U.S. attorney in the District before joining the firm of Whiteford, Hart, Carmody and Wilson in 1956.

After working briefly at the Washington office of Ober, Kaler, Mr. Strickler became general counsel for Washington Gas in 1985. He retired in 1990.

He was a fellow of the American College of Trial Lawyers and a member of the Barristers Club, Kiwanis Club and Congressional Country Club.

Survivors include his wife of 57 years, Ellis Barnard Strickler of Chevy Chase; four children, Charles B. Strickler of Chevy Chase, Elizabeth A. Strickler of Takoma Park, Frank H. Strickler Jr. of Huntley, Va., and Nancy Strickler Borah of Baltimore; and three grandchildren.

Early in the Watergate investigation, Mr. Strickler went to the White House to interview Nixon, Ehrlichman and Haldeman.

In one of Nixon’s White House tapes, the president spoke about the lawyer: “Strickler, he just looks sort of like a big country bumpkin, but there is a sharp mind in there.”