It was such an awful year in 2021. It was entirely fitting that it ended with the death on Dec. 29 of my oldest friend, Rufus C. Phillips III. I call him my “oldest friend” not because I had known him longer than anyone else but because he was 92 when he died of complications of pneumonia at a hospital in northern Virginia.

Had you met him, you would never have noticed his advanced age. He was active to the end, working on a book that will come out this year from the University Press of Kansas: “Stabilizing Fragile States: Why It Matters and What to Do About It.” I have been reading it and find it a font of good sense based on the author’s firsthand knowledge not only of the war in Vietnam but also of the more recent conflict in Afghanistan.

It was because of Rufus’s role in Vietnam that I met him — and I quickly found that he was not only an invaluable source of historical insights but also a wonderful person, one of the truest gentlemen I have ever known. Meeting Rufus for the first time around 2010 helped inspire me to write a book about his mentor, the legendary counterinsurgency adviser Edward Lansdale, who helped to defeat a communist uprising in the Philippines in the early 1950s and went on to help create the state of South Vietnam in 1954-1956. I developed a close friendship with Rufus during the many hours he spent patiently answering my questions.

As Rufus recounted in his memoir, “Why Vietnam Matters: An Eyewitness Account of Lessons Not Learned,” he first arrived in Saigon in August 1954 as a young Yale graduate recently enlisted in the CIA. Taken under Lansdale’s wing, Rufus was given a crash course in political warfare — what would later become known, somewhat misleadingly, as the battle for “hearts and minds.” His instructions were simply to “make friends, see what they were doing, and figure out how to help.”

Against all odds, Lansdale and his small team helped the new prime minister, Ngo Dinh Diem, consolidate his authority against the challenges posed by both communist fighters and warlord militias. Serving as an adviser to the newly created army of South Vietnam, Rufus helped the troops in 1955 to pacify a region newly vacated by the communist-dominated Vietminh. His key advice was simply for the soldiers to treat the local people with kindness and respect — a reflection of the way that Rufus himself dealt with everyone he met.

Later, in 1962, Rufus returned to South Vietnam to work for the U.S. Agency for International Development as head of “rural affairs” — which, in effect, made him the U.S. director of counterinsurgency at a time when the communists, now known as the Vietcong, were on the march. Because he knew so many Vietnamese so well, he realized that the rosy assessments being advanced by the Pentagon bore little relation to reality — and he wasn’t afraid to say so.

In a White House meeting on Sept. 10, 1963, Rufus told John F. Kennedy, “I am sorry to tell you, Mr. President, but we are not winning the war.” Rufus argued that the United States should pressure Diem to sideline his autocratic brother, Ngo Dinh Nhu, by sending Lansdale back to Saigon. Instead, the Kennedy administration supported a military coup against Diem that exacerbated the instability — and led directly to a massive military intervention that Lansdale and Rufus had warned against.

After the publication of his memoir in 2008, Rufus was enlisted as an adviser to U.S. officials directing the Afghanistan War. He spent his 80th birthday in Kabul observing that country’s fraud-marred election in 2009. Seeing how deeply flawed the U.S. effort in Afghanistan was, as he writes in “Stabilizing Fragile States,” he became convinced that “some serious reform is needed regarding how our foreign policy apparatus works to help stabilize fragile, failed and failing states.” His new book is an important primer on the subject.

But really all that future U.S. diplomats, military personnel and intelligence officers need to know is that they should act the way that Rufus would have. He had an inexhaustible font of decency and empathy for everyone he came into contact with. He made lifelong friends in Vietnam and everywhere else he went.

While another legendary adviser in Vietnam, John Paul Vann, had a famously checkered private life, Rufus was a model of love and devotion to his wonderful wife of 59 years, Barbara, a top-level translator for the State Department who died in 2020. They had four children and six grandchildren — all of whom were with Rufus at the end.

Much has been written about “ugly Americans.” Rufus Phillips was the opposite. Like the aid worker Bob Gersony, who was profiled in a book by Robert D. Kaplan, he was a genuine “good American” — a gentle, decent man who served his country with humility and devotion and fearless truth-telling. Let us hope his example inspires others.