The cause was congestive heart failure, said Clark Hoyt, with whom Mr. Boyd shared the Pulitzer for their reporting on the Eagleton story.
Starting in 1967, Mr. Boyd spent two decades as Washington bureau chief of Knight Newspapers and then Knight Ridder, a now-defunct newspaper chain whose once-muscular reach extended from Miami to San Jose.
The towheaded 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 there in 1965, to Hanoi in 1970 amid the Vietnam War, and to Communist China accompanying President Richard M. Nixon on a groundbreaking February 1972 diplomatic visit.
But the expedition for which Mr. Boyd was best remembered was a trek to the Black Hills of South Dakota that July to inform the presidential campaign of Sen. George S. McGovern (D-S.D.) 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, who had long denounced the conflict.
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 Sen. Edward M. Kennedy (D-Mass.).
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 a tip from an anonymous caller that Eagleton was trying to hide the full extent of his health, Mr. Boyd’s colleague 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.
(The tipster, Hoyt said, was a friend of the doctor who had been involved in Eagleton’s treatment. The friend was a McGovern supporter who had wanted the disclosure to come out fast in the hope that Nixon’s team would not use it as an “October surprise” close to the general election.)
With that information, the Knight Newspaper reporters showed up unannounced in South Dakota to confront McGovern’s team with their investigation.
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 in return 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 spoiled the scoop by compelling Eagleton to reveal at a news conference he had “voluntarily” undergone treatment for nervous exhaustion and depression three times since 1960. Eagleton also said his treatment regimen included psychiatric counseling, chemotherapy and electric-shock treatment.
As what a McGovern aide later called a “consolation prize,” Mr. Boyd and Hoyt were allowed a private trip to the Rapid City, S.D., airport with Eagleton.
“Still in the sweat-soaked sport jacket and open-collared shirt he wore at the news conference, Eagleton sat in the back seat of a sedan and answered all our questions reluctantly but graciously,” Hoyt later wrote. “He chain-smoked unfiltered Pall Malls, lighting one from another and throwing the butts out the window as we sped through a national forest.”
McGovern, who had initially declared himself “1,000 percent” behind Eagleton, soon reversed that stance. Eighteen days after Eagleton had been named to the ticket, he was replaced by Sargent Shriver, the Peace Corps founder and Kennedy in-law. McGovern lost in a landslide, despite foreshocks of the Watergate scandal that would topple Nixon two years later.
“What we did right was we didn’t just run with an incomplete story when we really didn’t have the full facts and properly confirmed,” said Hoyt, who later succeeded Mr. Boyd as bureau chief and 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 under the pressure of knowing we were there.”
Robert Skinner Boyd was born in Chicago on Jan. 11, 1928. As a boy, he accompanied his father, a top department-store executive who worked in and out of government, on assignments to Europe and Africa. After his parents divorced, he was raised by his mother, a public 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 Marine.
For one assignment, he recalled ferrying hundreds of horses to Poland to help with farming, but the animals were slaughtered to feed a starving postwar population. He was shaken by the memory of Polish mothers begging the Americans to take their children in the hope of a better life.
After completing his Harvard degree in 1949 magna cum laude, Mr. Boyd was recruited to the CIA and assigned to the Swiss desk. He grew discontented with work that required his findings to remain secret.
Turning to journalism in 1953, he joined a paper in Lafayette, La., where his French skills helped him uncover bayou mischief, including a cattle smuggling operation. He subsequently became state editor of a newspaper in Benton Harbor, Mich., and then general assignment reporter at the Detroit Free Press, a major paper of what was then Knight Newspapers.
He was promoted to Washington correspondent in 1960, in time to cover the Bay of Pigs fiasco. In 1965, he and journalist David Kraslow co-wrote an espionage novel, “A Certain Evil,” involving a reporter swept up in a CIA coup attempt in the Caribbean.
After stepping down from management, Mr. Boyd spent many years as chief correspondent and science writer for Knight Ridder (once trekking to the South Pole on assignment). He received a John S. Knight Journalism Fellowship in 1981 at Stanford University and was a past president of the Gridiron Club, a journalistic organization in Washington. He moved to Philadelphia from Bethesda, Md., in 2018.
His first marriage, to Gloria Paulsen, ended in divorce. In 1983, he married Ann Cullingworth. In addition to his wife, of Philadelphia, survivors include four children from his first marriage, Peter Boyd of Darnestown, Md., Susan Allan of Milwaukie, Ore., Andrew Boyd of Seattle and Tim Boyd of Winchester, Mass.; a daughter from his second marriage, Hollis McLaughlin of Philadelphia; two stepchildren, Jennifer Lauchlan of Arlington, Mass., and Harry Rust V of Takoma Park, Md.; 13 grandchildren; and three great-grandchildren.
Hoyt recalled Mr. Boyd as a low-key workhorse, not above tidying the bureau with a vacuum or taking intern-caliber assignments when no one else was free.
“Bob had come back from reporting in North Vietnam,” Hoyt said, “and he’s in the bureau typing his eyewitness account of the war, when he gets a call from the editor of the Charlotte Observer. A kid they had sponsored in a national spelling bee had become a finalist, and someone had to get over and cover it for them.”
Mr. Boyd, he said, saw his staff engaged and dropped his half-written Vietnam story to fill in covering the bee.
“He had an incredible intellect and curiosity about everything,” Hoyt said. “He had a passion for stories but not making himself the center of it.”