WASHINGTON — Robert Boyd, a journalist whose unearthing of 1972 Democratic vice presidential nominee Thomas F. Eagleton’s mental-health history — including shock-therapy treatment for depression — caused Eagleton to withdraw from the campaign and earned a Pulitzer Prize for national reporting, died Sept. 18 at a Philadelphia retirement home. He was 91.
The cause was congestive heart failure, said Clark Hoyt, with whom Mr. Boyd shared the Pulitzer.
Starting in 1967, Mr. Boyd spent two decades as Washington bureau chief of Knight Newspapers and then Knight Ridder, a now-defunct newspaper chain.
Mr. Boyd, who had once been in the CIA, was an idiosyncratic blend of Midwestern reserve and Harvard erudition: plain-spoken, but in six languages. Averse to punditry, he was not a marquee name on the Sunday talk-show circuit but commanded door-opening respect in political circles.
His career included notable reporting trips to Cuba after the failed Bay of Pigs invasion in 1961, to the Dominican Republic during a revolt in 1965, to Hanoi in 1970 amid the Vietnam War, and to Communist China accompanying President Nixon on a groundbreaking February 1972 diplomatic visit.
But the expedition for which Mr. Boyd was best remembered was a trek to South Dakota that July to inform the presidential campaign of Democratic Senator George McGovern that his recently selected running mate had not been entirely forthcoming about his mental-health history.
Little known outside his home state of Missouri, Eagleton was a bright, witty, and telegenic first-term senator whose ardent opposition to the Vietnam War made him a natural political ally of McGovern.
At 42, Eagleton served as a youthful counterweight to the World War II-era combat pilot at the top of the ticket. In all, he seemed a sensible second choice after McGovern’s failed courtship of Massachusetts Senator Edward Kennedy.
McGovern announced his selection of Eagleton on July 13. At a time when psychiatric care carried a politically insurmountable stigma, McGovern’s staff had been aware of Eagleton’s earlier hospitalization for fatigue and other rumors circulating about his mental health, but the campaign plowed forward with assurances that his time under care was brief.
Acting on an anonymous tip that Eagleton was trying to hide the full extent of his health, Hoyt dug further and gleaned enough information — from a doctor at a St. Louis psychiatric hospital — to feel confident he was on the right track.
Mr. Boyd and Hoyt showed up unannounced in South Dakota to confront McGovern’s team.
They turned over a two-page memo of their findings, including Eagleton’s history of depression that at least twice had required hospitalization and electroshock therapy. They gave the campaign an opportunity to respond, hoping for official corroboration and an exclusive interview with Eagleton.
‘‘It was the only fair and decent thing to do,’’ Mr. Boyd told the Harvard Crimson decades later.
After keeping the journalists hanging for a day or two, the campaign compelled Eagleton to reveal at a news conference that he had ‘‘voluntarily’’ undergone treatment for nervous exhaustion and depression three times since 1960. Eagleton also said his treatment included psychiatric counseling, chemotherapy, and electric shock.
Mr. Boyd and Hoyt were allowed a trip to the Rapid City, S.D., airport with Eagleton.
McGovern, who had initially declared himself ‘‘1,000 percent’’ behind Eagleton, soon reversed himself. Eighteen days after Eagleton had been named to the ticket, he was replaced by Sargent Shriver. McGovern lost in a landslide.
‘‘What we did right was we didn’t just run with an incomplete story,’’ said Hoyt, who later became public editor at the New York Times. ‘‘We tried to be responsible and report it out correctly, and they made a choice, to announce it to [the] world.’’
Robert Skinner Boyd was born in Chicago on Jan. 11, 1928. As a boy, he accompanied his father, a department-store executive, on assignments to Europe and Africa. After his parents divorced, he was raised by his mother, a librarian.
By the time he graduated in 1945 from the private Phillips Academy in Andover, Mass., he was fluent in French, Greek, and Sanskrit. He entered Harvard University with the ambition of becoming a linguistic scholar, but his schooling was interrupted by stints in the Army and the Merchant Marines.
Turning to journalism in 1953, he joined a paper in Lafayette, La., where his French skills helped him uncover bayou mischief. He subsequently became state editor of a newspaper in Benton Harbor, Mich., and then a reporter at the Detroit Free Press.