Mr. Buckley, described by a colleague as “one of the great swashbuckling reporters of the Vietnam era,” spent four years reporting from the front lines of the Vietnam War from 1968 to 1972.
He arrived at age 27, not much older than the young soldiers he covered. He soon became Newsweek’s bureau chief in the former capital city of Saigon (now Ho Chi Minh City). Most reporters at that time, he said, still supported the U.S. war effort and accepted the official statements from military leaders. But Mr. Buckley’s experience on the ground gradually made him more disillusioned.
“When I arrived in Vietnam,” he told the Yale Daily News in 2009, “the question was: ‘How are we doing?’ It was only later that I switched it to: ‘What are we doing?’ ”
One of Mr. Buckley’s most revelatory stories from Vietnam was his last, printed in Newsweek in June 1972. The previous year, he and a Vietnamese-speaking Newsweek reporter, Alexander Shimkin, found evidence of a prolonged U.S. military operation called Speedy Express that devastated the Mekong Delta province of Kien Hoa in 1968 and 1969.
“I traveled throughout Kien Hoa — on foot, by jeep, in boats and by raft — to talk with the people,” Mr. Buckley wrote in his Newsweek story. “All the evidence I gathered pointed to a clear conclusion: a staggering number of noncombatant civilians — perhaps as many as 5,000 according to one official — were killed by U.S. firepower to ‘pacify’ Kien Hoa.”
More recent estimates have placed the number of civilian deaths as high as 7,000. Thousands of others were wounded. The carnage was much greater than at My Lai, a village in which as many as 500 Vietnamese civilians were killed by U.S. troops in 1968. An Army lieutenant, William Calley, was the only military officer convicted of wrongdoing in the My Lai Massacre.
“Virtually every person to whom I spoke had suffered in some way,” Mr. Buckley wrote. “‘There were 5,000 people in our village before 1969, but there were none in 1970,’ one village elder told me. ‘The Americans destroyed every house with artillery, airstrikes or by burning them down with cigarette lighters.’ ”
Mr. Buckley was furious with his editors at Newsweek for delaying publication of his account by almost six months and for cutting some of its more damning details. (Shimkin, his fellow reporter, was killed in a North Vietnamese grenade attack in July 1972.)
The published article contained no references to Maj. Gen. Julian J. Ewell, the commanding general in charge of the 9th Infantry Division, which carried out Operation Speedy Express. Ewell was later promoted, and no military officers who took part in the attacks were court-martialed.
Mr. Buckley’s struggles to have his story told were recounted in Phillip Knightley’s 1975 book about war correspondents, “The First Casualty,” and in Nick Turse’s 2013 book, “Kill Anything that Moves: The Real American War in Vietnam.”
After a one-year journalism fellowship at Harvard University, Mr. Buckley left Newsweek in the mid-1970s and embarked on a varied career, often working for struggling publications, including New Times and a revived Look magazine. For six years, he was the editor of a U.S. version of Geo, a glossy European magazine about travel and social issues, before it folded in 1985.
He later became the top editor of Lear’s, a start-up magazine for older women. Mr. Buckley came up with the magazine’s catchy slogan — “For the woman who wasn’t born yesterday” — but after disagreements with its mercurial founder, Frances Lear, he was gone before the first issue was published in 1988.
By then, Mr. Buckley was researching the murky relationship between the United States and Manuel Antonio Noriega, the dictatorial military leader of Panama. In a 1991 book, “Panama: The Whole Story,” he described Noriega’s long-standing ties to U.S. intelligence agencies, which sought his help in arming the contras, a counterrevolutionary force in Nicaragua. Noriega was later accused of human rights abuses and coordinating with drug cartels before he was ousted in a 1989 coup, abetted by U.S. military troops.
In a New York Times review of Mr. Buckley’s book, political scientist Jorge G. Castaneda called it “an extraordinary account of a largely untold, dramatically underreported and often unbelievable story.”
Kevin Paul Buckley was born Dec. 31, 1940, in New York City. His family later moved to Larchmont, N.Y. His father was a government official, and his mother was a homemaker.
Mr. Buckley was a 1962 graduate of Yale University, where he was managing editor of the Yale Daily News. He worked for the Associated Press in Chicago before joining Newsweek as a religion writer.
“I wrote two cover stories,” he later said. “One had the lowest newsstand sale in Newsweek history: ‘The New Missionary.’ I guess I was missing one word: ‘Position.’ ”
He was well-liked by his fellow journalists, who noted his humor, wit and jaunty, idiosyncratic slang. When setting out on foot, he would invariably say, “Let’s ankle.”
While working in Newsweek’s London bureau in the 1960s, Mr. Buckley told the Yale Daily News, “I got to meet Jimi Hendrix and Mick Jagger, who came over, went through my records, put on one of his own and just started Jagging around my living room.”
Unmarried for many years, Mr. Buckley was linked to a number of glamorous women, including writer Frances FitzGerald, author of “Fire in the Lake,” about the Vietnam War.
“He certainly did have a great deal of charm and was incredibly good-looking,” FitzGerald said in an interview. “He was quite dashing.”
She added that he later introduced her to her future husband — and she introduced Mr. Buckley to his future wife, writer Gail Lumet Buckley, the daughter of entertainer Lena Horne.
In addition to his wife of 37 years, survivors include two stepdaughters; a brother; a sister; and two grandchildren.
Beginning in 1992, Mr. Buckley spent more than 10 years as executive editor of Playboy magazine, in charge of nonfiction articles.
“It’s a great magazine,” he later said. “And I admire Playboy’s defense of the First Amendment. What’s coming out of the Pentagon — that’s the real pornography.”
He also taught journalism at Columbia University and was a longtime member and officer of the Century Association, a private club of artists and writers in New York.
During his brief tenure at Lear’s magazine, Mr. Buckley told the Yale Daily News, one of his jobs was to hire a staff astrologer.
“In the interview, she said, ‘Can I be honest, Mr. Buckley?” he recalled. “‘Your future at this magazine looks very cloudy.’ I said, ‘That’s it! You’re hired!’”
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