In another approach, in the 1990s, he poured millions into what critics called a moral crusade against Mr. Clinton and his wife, Hillary Rodham Clinton, financing investigations by publications, notably the conservative American Spectator and his own Pittsburgh Tribune-Review, that were aimed at discrediting the Clintons.

They accused the Clintons of fraud in the Whitewater case, a failed real estate venture in the 1970s and ’80s, when Mr. Clinton was governor of Arkansas, and Mr. Clinton of sexual misconduct in liaisons with Paula Jones in Little Rock and Monica Lewinsky in the White House. They also charged that Vincent W. Foster Jr., a White House counsel and former law partner of Mrs. Clinton, had been murdered in 1993 in a Whitewater cover-up. Several investigations found that Mr. Foster had committed suicide.

The accusations, which prompted Mrs. Clinton to say on national television that her husband was the target of a “vast right-wing conspiracy,” troubled the administration for most of its tenure. They led to the convictions of 15 people in criminal cases, the appointment of a special prosecutor and the president’s impeachment by the House on perjury and obstruction of justice charges and his acquittal by the Senate, both by largely partisan votes.

During the Whitewater hearings in 1998, it was disclosed that the special prosecutor, Kenneth W. Starr, had accepted a job as dean of the public policy school at Pepperdine University in Malibu, Calif. He reversed his decision after the Justice Department said it might be a conflict of interest because Mr. Scaife was a Pepperdine regent and a major donor to the university and its public policy chairman.

Mr. Scaife gave millions to what he called nonpolitical campus, community and church organizations that promoted conservative causes; public interest law firms; and consumer and environmental groups that actually promoted business interests. Critics say liberal groups have long acted with similar deceptions. He also gave to the Pittsburgh Symphony Orchestra, the Carnegie Institute, the National Gallery of Art, other museums, hospitals, the Corporation for Public Broadcasting and Planned Parenthood.

In 2008, Mrs. Clinton, then a Democratic senator from New York running for president, met Mr. Scaife and editors and reporters of The Pittsburgh Tribune-Review for an interview. The newspaper endorsed her, and Mr. Scaife, in a commentary, said: “I have a very different impression of Hillary Clinton today. And it’s a very favorable one indeed.”

Richard Mellon Scaife was born in Pittsburgh on July 3, 1932, one of two children of Alan Magee Scaife and Sarah Cordelia Mellon Scaife. His father was the scion of a Pittsburgh steel family, and his mother was the daughter of Richard B. Mellon, who made fortunes in banking and oil, and a niece of Andrew W. Mellon, the Treasury secretary in the Harding, Coolidge and Hoover administrations.