Henry Kissinger, The Architect of China shift to US from Russia is no more

The most powerful secretary of state of the postwar era, he was both celebrated and reviled. His complicated legacy still resonates in relations with China, Russia and the Middle East.

[ABS News Service/30.11.2023]

Henry A. Kissinger, the scholar-turned-diplomat who engineered the United States’ opening to China, negotiated its exit from Vietnam, and used cunning, ambition and intellect to remake American power relationships with the Soviet Union at the height of the Cold War, sometimes trampling on democratic values to do so, died on Wednesday at his home in Kent, Conn. He was 100.

His death was announced in a statement by his consulting firm.

Few diplomats have been both celebrated and reviled with such passion as Mr. Kissinger. Considered the most powerful secretary of state in the post-World War II era, he was by turns hailed as an ultrarealist who reshaped diplomacy to reflect American interests and denounced as having abandoned American values, particularly in the arena of human rights, if he thought it served the nation’s purposes.

He advised 12 presidents — more than a quarter of those who have held the office — from John F. Kennedy to Joseph R. Biden Jr. With a scholar’s understanding of diplomatic history, a German-Jewish refugee’s drive to succeed in his adopted land, a deep well of insecurity and a lifelong Bavarian accent that sometimes added an indecipherable element to his pronouncements, he transformed almost every global relationship he touched.

At a critical moment in American history and diplomacy, he was second in power only to President Richard M. Nixon. He joined the Nixon White House in January 1969 as national security adviser and, after his appointment as secretary of state in 1973, kept both titles, a rarity. When Nixon resigned, he stayed on under President Gerald R. Ford.

Mr. Kissinger’s secret negotiations with what was then still called Red China led to Nixon’s most famous foreign policy accomplishment. Intended as a decisive Cold War move to isolate the Soviet Union, it carved a pathway for the most complex relationship on the globe, between countries that at Mr. Kissinger’s death were the world’s largest (the United States) and second-largest economies, completely intertwined and yet constantly at odds as a new Cold War loomed.

For decades he remained the country’s most important voice on managing China’s rise, and the economic, military and technological challenges it posed. He was the only American to deal with every Chinese leader from Mao to Xi Jinping. In July, at age 100, he met Mr. Xi and other Chinese leaders in Beijing, where he was treated like visiting royalty even as relations with Washington had turned adversarial.

He drew the Soviet Union into a dialogue that became known as détente, leading to the first major nuclear arms control treaties between the two nations. With his shuttle diplomacy, he edged Moscow out of its standing as a major power in the Middle East, but failed to broker a broader peace in that region.

Over years of meetings in Paris, he negotiated the peace accords that ended the American involvement in the Vietnam War, an achievement for which he shared the 1973 Nobel Peace Prize. He called it “peace with honor,” but the war proved far from over, and critics argued that he could have made the same deal years earlier, saving thousands of lives.

Within two years, North Vietnam had overrun the American-backed South. It was a humiliating end to a conflict that from the beginning Mr. Kissinger had doubted the United States could ever win.

To his detractors, the Communist victory was the inevitable conclusion of a cynical policy that had been intended to create some space between the American withdrawal from Vietnam and whatever came next. Indeed, in the margins of the notes for his secret trip to China in 1971, Mr. Kissinger scribbled, “We want a decent interval,” suggesting he simply sought to postpone the fall of Saigon.

But by the time that interval was over, Americans had given up on the Vietnam project, no longer convinced that the United States’ strategic interests were linked to that country’s fate.

As was the case with Vietnam, history has judged some of his Cold War realism in a harsher light than it was generally portrayed at the time. With an eye fixed on the great power rivalry, he was often willing to be crudely Machiavellian, especially when dealing with smaller nations that he often regarded as pawns in the greater battle.

He was the architect of the Nixon administration’s efforts to topple Chile’s democratically elected Socialist president, Salvador Allende.

He has been accused of breaking international law by authorizing the secret carpet-bombing of Cambodia in 1969-70, an undeclared war on an ostensibly neutral nation.

His objective was to root out the pro-Communist Vietcong forces that were operating from bases across the border in Cambodia, but the bombing was indiscriminate: Mr. Kissinger told the military to strike “anything that flies or anything that moves.” At least 50,000 civilians were killed.

When Pakistan’s U.S.-backed military was waging a genocidal war in East Pakistan, now Bangladesh, in 1971, he and Nixon not only ignored pleas from the American consulate in East Pakistan to stop the massacre, but they approved weapons shipments to Pakistan, including the apparently illegal transfer of 10 fighter-bombers from Jordan.

Mr. Kissinger and Nixon had other priorities: supporting Pakistan’s president, who was serving as a conduit for Kissinger’s then-secret overtures to China. Again, the human cost was horrific: At least 300,000 people were killed in East Pakistan and 10 million refugees were driven into India.

In 1975, Mr. Kissinger and President Ford secretly approved the invasion of the former Portuguese colony of East Timor by Indonesia’s U.S.-backed military. After the loss of Vietnam, there were fears that East Timor’s leftist government could also go Communist.

Mr. Kissinger told Indonesia’s president that the operation needed to succeed quickly and that “it would be better if it were done after we returned” to the United States, according to declassified documents from Mr. Ford’s presidential library. More than 100,000 East Timorese were killed or starved to death.

Mr. Kissinger dismissed critics of these moves by saying that they did not face the world of bad choices he did. But his efforts to snuff out criticism with sarcastic one-liners only inflamed it.

“The illegal we do immediately,” he quipped more than once. “The unconstitutional takes a little longer.”

On at least one potentially catastrophic stance Mr. Kissinger later reversed himself.

Starting in the mid-1950s as a young Harvard professor, he argued for the concept of limited nuclear war — a nuclear exchange that could be contained to a specific region. In office, he worked extensively on nuclear deterrence — convincing an adversary, for instance, that there was no way to launch a nuclear strike without paying an unacceptably high price.

But he later conceded that it might be impossible to prevent a limited nuclear war from escalating. By the end of his life he had embraced, with reservations, a new effort to gradually eliminate all nuclear weapons and, at age 95, he began to warn of the instability posed by the rise of weapons driven by artificial intelligence.

“All I can do in the few years left of me is to raise these issues,” he said in 2018. “I don’t pretend to have the answers.”

Mr. Kissinger remained influential to the end. His latest writings on managing a rising China — including “On China” (2011), a 600-page book that mixed history with self-reverential anecdotes — could be found on the bookshelves of West Wing national security aides who followed him.

Relevant Into His 90s

Fifty years after he joined the Nixon administration, Republican candidates still sought Mr. Kissinger’s endorsement and presidents sought his approval. Even Mr. Trump, after lambasting the Republican establishment, visited him during his 2016 campaign in the hope that the mere image of his seeking Mr. Kissinger’s advice would convey gravitas. (It yielded a New Yorker cartoon in which Mr. Kissinger is shown with a thought-bubble above his head reading, “I miss Nixon.”)

Mr. Kissinger laughed about the fact that Mr. Trump could not name, when New York Times reporters asked, a single new idea or initiative that he had taken away from the meeting. “He’s not the first person I’ve advised who either didn’t understand what I was saying or didn’t want to,” he said. Still, once in office, Mr. Trump used him as a back channel to the Chinese leadership.

President Barack Obama, who was 8 years old when Mr. Kissinger first took office, was less enamored of him. Mr. Obama noted toward the end of his presidency that he had spent much of his tenure trying to repair the world that Mr. Kissinger left. He saw Mr. Kissinger’s failures as a cautionary tale.

“We dropped more ordnance on Cambodia and Laos than on Europe in World War II,” Mr. Obama said in an interview with The Atlantic in 2016, “and yet, ultimately, Nixon withdrew, Kissinger went to Paris, and all we left behind was chaos, slaughter and authoritarian governments that finally, over time, have emerged from that hell.”

Mr. Obama noted that while in office he was still trying to help countries “remove bombs that are still blowing off the legs of little kids.”

“In what way did that strategy promote our interests?” he said.

Few figures in modern American history remained so relevant for so long as Mr. Kissinger. Well into his 90s he kept speaking and writing, and charging astronomical fees to clients seeking his geopolitical analysis.

While the protesters at his talks dwindled, the very mention of his name could trigger bitter arguments. To his admirers, he was the brilliant architect of Pax Americana, the chess grandmaster who was willing to upend the board and inject a measure of unpredictability into American diplomacy.

To his detractors — and even some friends and former employees — he was vain, conspiratorial, arrogant and short-tempered, a man capable of praising a top aide as indispensable while ordering the F.B.I. to illegally tap his home phones to see if he was leaking to the press.

The irony was not lost on two generations of reporters, who knew that if they were looking for leaks — usually self-interested ones — Mr. Kissinger, a master of the art, was a ready source. “If anybody leaks in this administration, I will be the one to leak,” he said. And he did, prodigiously.

To read Mr. Kissinger’s laudatory 1957 book analyzing the world order created by Prince Klemens von Metternich of Austria, who led the Austrian empire in the post-Napoleonic era, is also to read something of a self-description, particularly when it came to the ability of a single leader to bend nations to his will.

“He excelled at manipulation, not construction,” Mr. Kissinger said of Metternich. “He preferred the subtle maneuver to the frontal attack.”

That style was demonstrated during the Nixon years as the Watergate scandal unfolded. Increasingly isolated, Nixon often turned to Mr. Kissinger, the undiminished star of his administration, for reassurance and a recitation of his greatest achievements.

He would oblige. The Watergate tapes revealed Mr. Kissinger spending humiliating hours listening to the president’s harangues, including antisemitic comments delivered to his Jewish secretary of state. Mr. Kissinger often responded with flattery. After returning to his office, he would roll his eyes as he told his closest colleagues about Nixon’s bizarre behavior.

Leaks and Paranoia

Mr. Kissinger was not involved in the Watergate affair. Yet the break-in at the offices of the Democratic National Committee by a White House team of burglars and the administration’s attempts to cover up the crime emerged from a culture of suspicion and secretiveness that many argue that he helped foster.

In the spring of 1969, soon after taking office, he was so enraged by the leaks behind a Times report on the Cambodia bombing campaign that he ordered the F.B.I. to tap the phones of more than a dozen White House aides, including members of his own staff. The recordings never turned up a culprit.

He was similarly infuriated by the publication of the Pentagon Papers in The Times and The Washington Post in 1971. The classified documents chronicled the government’s war policies and planning in Vietnam, and leaking them, in his view, jeopardized his secret face-to-face diplomacy. His complaints helped inspire the creation of the White House burglary team, the leak-plugging Plumbers unit that would later break into Democratic headquarters at the Watergate building.

In August 1974, as Nixon reconciled himself to the choice between impeachment and resignation, he drew Mr. Kissinger into one of the most operatic moments in White House history. Having told Mr. Kissinger that he intended to resign, a distraught Nixon asked his secretary of state to kneel with him in silent prayer outside the Lincoln Sitting Room.

Yet, as Nixon sank deeper into Watergate, Mr. Kissinger attained a global prominence few of his successors have matched.

Aides described his insights as brilliant and his temper ferocious. They told stories of Mr. Kissinger throwing books across his office in towering rages, and of a manipulative streak that led even his most devoted associates to distrust him.

“In dealing with other people he would forge alliances and conspiratorial bonds by manipulating their antagonisms,” Walter Isaacson wrote in his comprehensive 1992 biography, “Kissinger,” a book its subject despised.

“Drawn to his adversaries with a compulsive attraction, he would seek their approval through flattery, cajolery and playing them off against others,” Mr. Isaacson observed. “He was particularly comfortable dealing with powerful men whose minds he could engage. As a child of the Holocaust and a scholar of Napoleonic-era statecraft, he sensed that great men as well as great forces were what shaped the world, and he knew that personality and policy could never be fully divorced. Secrecy came naturally to him as a tool of control. And he had an instinctive feel for power relationships and balances, both psychological and geostrategic.”

In old age, when the hard edges had been filed down and old rivalries had receded or been buried along with his former adversaries, Mr. Kissinger would sometimes talk about the comparative dangers of the global order he had shaped and a far more disorderly world facing his successors.

There was something fundamentally simple, if terrifying, in the superpower conflicts he navigated. He never had to deal with terrorist groups like Al Qaeda or the Islamic State, or a world in which nations use social media to manipulate public opinion and cyberattacks to undermine power grids and communications.

“The Cold War was more dangerous,” Mr. Kissinger said in a 2016 appearance at the New-York Historical Society. “Both sides were willing to go to general nuclear war.” But, he added, “today is more complex.”

The great-power conflict had changed dramatically from the cold peace he had tried to engineer. No longer ideological, it was purely about power. And what worried him most, he said, was the prospect of conflict with “the rising power” of China as it challenged the might of the United States.

Russia, in contrast, was “a diminished state,” and no longer “capable of achieving world domination,” he said in a 2016 Times interview in Kent, in northwest Connecticut, where he kept a second home. His primary residence was in Manhattan.

Yet he warned against underestimating Vladimir V. Putin, the Russian leader. Making reference to Hitler’s autobiographical manifesto, he said: “In order to understand Putin, one has to read Dostoyevsky, not ‘Mein Kampf.’ He believes Russia was cheated, that we keep taking advantage of it.”

Mr. Kissinger took some satisfaction in the fact that Russia was a lesser threat. After all, he had concluded the first strategic arms agreement with Moscow and steered the United States toward accepting the Helsinki Accords, the 1975 compact on European security that obtained some rights of expression for Soviet bloc dissidents. In retrospect, it was one of the droplets that turned into the river that swept away Soviet Communism.

Man About Town

At the height of his power, Mr. Kissinger cut a figure that no Washington diplomat has matched since. The pudgy, short Harvard professor with nerdy black glasses was seen in the Washington neighborhood of Georgetown and Paris with starlets on his arm, joking that “power is the greatest aphrodisiac.”

In New York restaurants with the actress Jill St. John, he would hold hands or run his fingers through her hair, giving gossip columnists a field day. In fact, as Ms. St. John told biographers, the relationship had been close but platonic.

So were others. One woman who dated him and returned to his small rented apartment on the edge of Rock Creek Park in Washington — with its single bed for sleeping and another that held a mass of laundry — reported that between the mess and the presence of aides, “you couldn’t do anything romantic in that place even if you were dying to.”

The joke in Washington was that Mr. Kissinger flaunted his private life to hide what he was doing at the office.

There was plenty to hide, notably the secret meetings in Beijing that carved out Nixon’s opening to China. When the turn toward China ultimately became public, it changed the strategic calculus of American diplomacy and shocked American allies.

“It’s almost impossible to imagine what the American relationship with the world’s most important rising power would look like today without Henry,” Graham Allison, a Harvard professor who once worked for Mr. Kissinger, said in an interview in 2016.

Other Kissinger efforts yielded mixed results. Through tireless shuttle diplomacy at the end of the Yom Kippur War in 1973, Mr. Kissinger was able to persuade Egypt to begin direct talks with Israel, an opening wedge to the later peace agreement between the two nations.

But perhaps the most important diplomatic contribution Mr. Kissinger made was his sidelining of Moscow in the Middle East for four decades, until Mr. Putin ordered his air force to enter the Syrian civil war in 2015.

Mr. Kissinger’s greatest failures came in his seeming indifference to the democratic struggles of smaller nations. Oddly, a man driven from his country as a boy by the rise of the Nazis seemed unperturbed by human rights abuses by governments in Africa, Latin America, Indonesia and elsewhere. Nixon’s Oval Office tapes showed that Mr. Kissinger was more concerned with keeping allies in the anti-Communist camp than with how they treated their own people.

For decades he would battle, often unconvincingly, accusations that he had turned a blind eye to human rights abuses. Perhaps the most egregious episode came in the signals to Pakistan that it was free to deal with Bengalis in East Pakistan as it saw fit.

In “The Blood Telegram: Nixon, Kissinger, and a Forgotten Genocide” (2013), the Princeton scholar Gary J. Bass depicts Mr. Kissinger ignoring warnings of an impending genocide, including those from the American consul general in East Pakistan, Archer Blood, whom he punished as disloyal.

In the Oval Office tapes, “Kissinger sneered at people who ‘bleed’ for ‘the dying Bengalis,’” Professor Bass wrote.

Divorced in 1964 after a 15-year marriage to Ann Fleischer, Mr. Kissinger married Nancy Maginnes in 1974 and moved to her home in Manhattan. Ms. Maginnes was then working for Nelson A. Rockefeller, the former New York governor and a friend and ally of Mr. Kissinger’s.

Mr. Kissinger never resumed teaching after leaving government service. But he continued to write at a pace that embarrassed his former academic colleagues for their relative slowness.

He produced three volumes of memoirs filling 3,800 pages: “The White House Years,” which focused on Nixon’s first term, 1969-73; “Years of Upheaval,” which dealt with the next two years; and finally “Years of Renewal,” which covered the Ford presidency. “World Order,” published in 2014, was something of a valedictory assessment of geopolitics in the second decade of the 21st century. In it, he expressed worry about America’s capacity for leadership.

“After withdrawing from three wars in two generations — each begun with idealistic aspirations and widespread public support but ending in national trauma — America struggles to define the relationship between its power (still vast) and its principles,” he wrote.

He continued to wield influence in world affairs, and through his firm, Kissinger Associates, he advised corporations and executives on international trends and looming difficulties. When Disney sought to navigate the Chinese leadership to build a $5.5 billion park in Shanghai, Mr. Kissinger got the call.

“Henry is certainly one of the most complex characters in recent American history,” said David Rothkopf, a former managing director of Mr. Kissinger’s consulting firm. “And he is someone who has, I think, justifiably been in the spotlight both for extraordinary brilliance and competence and, at the same time, clear defects.”

Escape to America

Heinz Alfred Kissinger was born on May 27, 1923, in the Bavarian town of Fürth. A year later, his parents, Louis Kissinger, a high school teacher, and Paula (Stern) Kissinger, the daughter of a prosperous cattle trader, had another son, Walter.

By all accounts young Heinz was withdrawn and bookish but passionate about soccer — so much so that he risked confrontations with Nazi toughs to see games even after signs had gone up at one stadium declaring “Juden Verboten.”

His parents raised him to be a faithful member of the orthodox Fürth synagogue, though in writing to them as a young adult he virtually rejected all religious practice.

Louis lost his job when the Nuremberg Laws were adopted in 1935; as a Jew he was barred from teaching in a state school. For the next three years Paula Kissinger took the initiative in trying to get the family out of the country, writing to a cousin in New York about immigrating.

In the fall of 1938, with war still a year away, the Nazi authorities permitted them to leave Germany. With little furniture and a single trunk, the Kissingers embarked for New York aboard the French ocean liner Ile de France. Heinz was 15.

It was not a moment too soon: At least 13 of the family’s close relatives perished in the Nazi gas chambers or concentration camps. Paula Kissinger recalled years later, “In my heart, I knew they would have burned us with the others if we had stayed.”

Mr. Kissinger played down the impact of those years on his worldview. He told an interviewer in 1971: “I was not consciously unhappy. I was not acutely aware of what was going on.” But in a Times interview several years ago he did relate painful memories — of the intimidation he felt in stepping into the street to avoid the Hitler Youth, and of the sadness of having to say goodbye to relatives, particularly his grandfather, whom he knew he would never see again.

Many of Mr. Kissinger’s acquaintances said his experiences in Nazi Germany had influenced him more than he acknowledged, or perhaps even knew.

“For the formative years of his youth, he faced the horror of his world coming apart, of the father he loved being turned into a helpless mouse,” said Fritz Kraemer, a non-Jewish German immigrant who was to become Mr. Kissinger’s first intellectual mentor. “It made him seek order, and it led him to hunger for acceptance, even if it meant trying to please those he considered his intellectual inferiors.”

Some have argued that Mr. Kissinger’s rejection of a moralistic approach to diplomacy in favor of realpolitik arose because he had borne witness to a civilized Germany embracing Hitler. Mr. Kissinger often cited an aphorism of Goethe’s, saying that if he were given the choice of order or justice, he, like the novelist and poet, would prefer order.

The Kissingers settled in Upper Manhattan, in Washington Heights, then a haven for German-Jewish refugees. His dispirited father got a job as a bookkeeper, but fell into depression and never fully adjusted to his adopted land. Paula Kissinger kept the family together, catering small parties and receptions.

Heinz became Henry in high school. He switched to night school when he took a job at a company making shaving brushes. In 1940, he enrolled in City College — tuition was virtually free — and racked up A’s in almost all his courses. He seemed headed to becoming an accountant.

Then, in 1943, he was drafted into the Army and assigned to Camp Claiborne in Louisiana.

It was there that Mr. Kraemer, a patrician intellectual and Prussian refugee, arrived one day to give a talk about the “moral and political stakes of the war,” as Mr. Kissinger recalled. The private returned to his barracks and wrote Mr. Kraemer a note: “I heard you speak yesterday. This is how it should be done. Can I help you in any way?”

The letter changed the direction of his life. Taking him under his wing, Mr. Kraemer arranged for Private Kissinger to be reassigned to Germany to serve as a translator. As German cities and towns fell in the last months of the war, Mr. Kissinger was among the first on the scene, interrogating captured Gestapo officers and reading their mail.

In April 1945, with Allied victory in sight, he and his fellow soldiers led raids on the homes of Gestapo members who were suspected of planning sabotage campaigns against the approaching American forces. For his efforts he received a Bronze Star.

But before returning to the United States he visited Fürth, his hometown, and found that only 37 Jews remained. In a letter discovered by Niall Ferguson, his biographer, Mr. Kissinger wrote at 23 that his encounters with concentration camp survivors had taught him a key lesson about human nature.

“The intellectuals, the idealists, the men of high morals had no chance,” the letter said. The survivors he met “had learned that looking back meant sorrow, that sorrow was weakness, and weakness synonymous with death.”

Mr. Kissinger stayed in Germany after the war — fearful, he said later, that the United States would succumb to a democracy’s temptation to withdraw its weary forces too fast and lose the chance to cement victory.

He took a job as a civilian instructor teaching American officers how to uncover former Nazi officers, work that allowed him to crisscross the country. He became alarmed by what he saw as Communist subversion of Germany and warned that the United States needed to monitor German phone conversations and letters. It was his first taste of a Cold War that he would come to shape.

He returned to the United States in 1947, intent on resuming his college education, only to be rejected by a number of elite universities. Harvard was the exception.

‘A New World’ in Cambridge

Mr. Kissinger entered Harvard as a sophomore, a member of the class of 1950. It was the beginning of his two decades on the campus in Cambridge, Mass., where he would find fame as a professor before clashing with colleagues over Vietnam so sharply that he would vow never to return.

He arrived on campus with his cocker spaniel, Smoky, whom he was forever hiding from his proctors in Claverly Hall, where dogs were prohibited. Friends later said that Smoky’s presence in the dorm had been telling: Mr. Kissinger had felt like a friendless immigrant again. “Harvard was a new world to me then,” he wrote, looking back, “its mysteries hidden behind studied informality.”

But the outsider now had direction, and he found another mentor in William Yandell Elliott, who headed the government department. Professor Elliott guided Mr. Kissinger toward political theory, even as he wrote privately that his student’s mind “lacks grace and is Teutonic in its systematic thoroughness.”

Under Professor Elliott, Mr. Kissinger wrote a senior thesis, “The Meaning of History,” focusing on Immanuel Kant, Oswald Spengler and Arnold Toynbee. At a hefty 383 pages, it gave rise to what became informally known at Harvard as “the Kissinger rule,” which limits the length of a senior thesis.

Mr. Kissinger graduated, summa cum laude, in 1950. Days later, the Korean War broke out, with the newly created People’s Republic of China and the Soviet Union backing North Korea’s Communist forces. He soon accepted some modest consulting work for the government that took him to Japan and South Korea.

Returning to Harvard to pursue a Ph.D., he and Professor Elliott started the Harvard International Seminar, a project that brought young foreign political figures, civil servants, journalists and an occasional poet to the university.

The seminar placed Mr. Kissinger at the center of a network that would produce a number of leaders in world affairs, among them Valéry Giscard d’Estaing, who would become president of France; Yasuhiro Nakasone, a future prime minister of Japan; Bulent Ecevit, later the longtime prime minister of Turkey; and Mahathir Mohamad, the future father of modern Malaysia.

With Ford Foundation support, the seminar kept his family eating as Mr. Kissinger worked on his dissertation on the diplomacy of Metternich of Austria and Robert Stewart Castlereagh, the British foreign secretary, after the Napoleonic wars. The dissertation, which became his first book, both shaped and reflected his view of the modern world.

The book, “A World Restored,” can be read as a guide to Mr. Kissinger’s later fascination with the balancing of power among states and his suspicion of revolutions. Metternich and Mr. Castlereagh sought stability in Europe and largely achieved it by containing an aggressive revolutionary France through an equilibrium of forces.

Mr. Kissinger saw parallels in the great struggle of his time: containing Stalin’s Soviet Union.

“His was a quest for a realpolitik devoid of moral homilies,” Stanley Hoffmann, a Harvard colleague who later split with Mr. Kissinger, said in 2015.

Mr. Kissinger received his Ph.D. in 1954 but received no offer of an assistant professorship. Some on the Harvard faculty complained that he had not poured himself into his work as a teaching fellow. They regarded him as too engaged in worldly issues. In fact, he was simply ahead of his time: The Boston-to-Washington corridor would soon become jammed with academics consulting with the government or lobbyists.

‘Limited Nuclear War’

The Harvard rejection embittered Mr. Kissinger. The Nixon tapes later caught him telling the president that the problem with academia was that “you are entirely dependent on the personal recommendation of some egomaniac.”

With the help of McGeorge Bundy, a Harvard colleague, Mr. Kissinger was placed in an elite study group at the Council on Foreign Relations, at the time a stuffy, all-male enclave in New York. Its mission was to study the impact of nuclear weapons on foreign policy.

Mr. Kissinger arrived in New York with a lot of attitude. He thought that the Eisenhower administration was wrongly reluctant to rethink American strategic policy in light of Moscow’s imminent ability to strike the United States with overwhelming nuclear force.

“Henry managed to convey that no one had thought intelligently about nuclear weapons and foreign policy until he came along to do it himself,” Paul Nitze, perhaps the country’s leading nuclear strategist at the time, later told Strobe Talbott, who was deputy secretary of state under President Bill Clinton.

Mr. Kissinger seized on a question that Mr. Nitze had begun discussing: whether America’s threat to go to general nuclear war against the Soviet Union was no longer credible given the commonly held view that any such conflict would invite only “mutually assured destruction.” Mr. Nitze asked whether it would be wiser to develop weapons to conduct a limited, regional nuclear war.

Mr. Kissinger decided that “limited nuclear war represents our most effective strategy.”

What was supposed to be a council publication became instead a Kissinger book, and his first best seller: “Nuclear Weapons and Foreign Policy.” Its timing, 1957, was perfect: It played into a national fear of growing Soviet power.

And its message fit the moment: If an American president was paralyzed by fear of escalation, Mr. Kissinger argued, the concept of nuclear deterrence would fail. If the United States could not credibly threaten to use small, tactical weapons, he said, it “would amount to giving the Soviet rulers a blank check.” In short, professing a willingness to conduct a small nuclear war was better than risking a big one.

To his critics, this was Mr. Kissinger at his Cold War worst, weaving an argument that a nuclear exchange could be won. Many scholars panned the book, believing its 34-year-old author had overestimated the nation’s ability to keep limited war limited. But to the public it was a breakthrough in nuclear thinking. To this day it is considered a seminal work, one that scholars now refer to in looking for lessons to apply to cyberwarfare.

The improbable success of the book led Mr. Kissinger back to Harvard as a lecturer. Two years later, Ann gave birth to their first child, Elizabeth; in 1961, their son, David, was born.

Coming to Power

Kissinger’s reputation had now been catapulted beyond academia; those who had never heard of Metternich wanted Mr. Kissinger involved in meeting the strategic threat of the era. He was called to a meeting organized by Mr. Rockefeller, then an assistant to President Dwight D. Eisenhower on international affairs. The patrician WASP and the Jewish immigrant formed an unlikely friendship, but one that gave Mr. Kissinger a patron with the resources of one of America’s greatest family fortunes, and gave Mr. Rockefeller someone to make him sound more credible on a global stage.

Mr. Kissinger said of Mr. Rockefeller, a future New York governor and vice president: “He has a second-rate mind but a first-rate intuition” about people and politics. “I have a first-rate mind but a third-rate intuition about people.”

Back at Harvard, his classes were popular, and the more Mr. Kissinger was interviewed on television, the bigger a star he became on campus. But he was soon immersed in the academic politics that he so despised, and his quest for tenure did not proceed smoothly. He and Zbigniew Brzezinski, who would become President Jimmy Carter’s national security adviser, were competitors, until Mr. Brzezinski left.

David Riesman, the sociologist and co-author of a seminal work on the American character, “The Lonely Crowd,” suggested that dinner with Mr. Kissinger was a chore. “He would not spend time chatting at the table,” Mr. Riesman said. “He presided.”

Leslie H. Gelb, then a doctoral student and later a Pentagon official and columnist for The Times, called him “devious with his peers, domineering with his subordinates, obsequious to his superiors.”

Tenure nonetheless arrived in 1959, an appointment announced by Mr. Bundy, who at 34 had become Harvard’s youngest dean of faculty. Mr. Kissinger later wrote that Mr. Bundy had treated him “with the combination of politeness and subconscious condescension that upper-class Bostonians reserve for people of, by New England standards, exotic backgrounds and excessively intense personal style.”

By 1961 Mr. Bundy was national security adviser to the newly elected president, John F. Kennedy, and Mr. Kissinger was swept up in the Harvard rush to the White House. But he was denied a senior job. He made end runs to see the president, but after a few sessions Kennedy himself cut them off. Mr. Kissinger said later, “I consumed my energies offering unwanted advice.”

At Harvard, he began organizing meetings on the emerging crisis of the day, Vietnam. He explored the link between military actions on the ground and the chances of success through diplomacy, seemingly convinced, even then, that the war could be ended only through negotiations.

After a long trip to Saigon and the front lines, he wrote that the American task was to “build a nation in a divided society in the middle of a civil war,” defining a problem that would haunt Washington not only in Southeast Asia but also in Afghanistan and Iraq.

He also renewed his relationship with Mr. Rockefeller, a moderate Republican who seemed like a good presidential prospect for 1968. And he met a tall, 30-year-old junior Rockefeller aide, Ms. Maginnes, whom he would marry years later.

Mr. Kissinger began writing speeches for Mr. Rockefeller and denouncing his most likely Republican rival for the White House, Richard M. Nixon, describing him as a disaster who could never be elected. But when Rockefeller’s star fell and Nixon won the nomination, he was invited to join Nixon’s foreign policy board. He kept his advisory role quiet, but it nonetheless led to one of the first big public disputes involving Mr. Kissinger and accusations of double-dealing.

With Lyndon B. Johnson’s White House engaged in peace talks with the North Vietnamese in Paris, Mr. Kissinger was said to have used his contacts on his own trips to Paris to funnel inside information back to Nixon. “Henry was the only person outside the government we were authorized to discuss the negotiation with,” Richard C. Holbrooke, who went on to key positions in the Clinton and Obama administrations, told Mr. Isaacson for his Kissinger biography. “We trusted him. It is not stretching the truth to say that the Nixon campaign had a secret source within the United States negotiating team.”

Nixon’s ‘Prized Possession’

Nixon himself referred in his memoirs to his “highly unusual channel” of information. To many who have since accepted that account, the back-channel tactic was evidence of Mr. Kissinger’s drive to obtain power if Nixon was elected. While there is no evidence that he supplied classified information to the Nixon campaign, there have long been allegations that Nixon used precisely that to give back-channel assurances to the South Vietnamese that they would get a better deal from him than from Johnson, and that they should agree to nothing until after the election.

Mr. Ferguson and other historians have rebutted that claim, though one of Nixon’s biographers found notes from H.R. Haldeman, one of Nixon’s closest aides, in which the presidential candidate ordered his staff to “monkey wrench” peace talks.

Whatever the truth, Mr. Kissinger was on Nixon’s radar. And after the election, a new president who had often expressed his disdain for Jews and Harvard academics chose, as his national security adviser, a man who was both.

Nixon directed Mr. Kissinger to run national security affairs covertly from the White House, cutting out the State Department and Nixon’s secretary of state, William P. Rogers. Nixon had found his man — a “prized possession,” he later called Mr. Kissinger.

While the post of national security adviser had grown in importance since Harry S. Truman established the role, Mr. Kissinger took it to new heights. He recruited bright young academics to his staff, which he nearly doubled. He effectively sidelined Mr. Rogers and battled the pugnacious defense secretary, Melvin R. Laird, moving more decision-making into the White House.

He met constantly with Nixon, often eschewing the practice of having staff members present when discussing their areas of expertise. He went in alone, unwilling to share either the glory or the intimacy of such occasions.

His rages were legendary. When he angrily stamps one foot, you’re OK, a former aide told Mr. Isaacson. When both feet leave the ground, the aide said, you’re in trouble. When Lawrence S. Eagleburger, a Kissinger personal aide and later briefly secretary of state, collapsed from overwork and was wheeled out to an ambulance, Mr. Kissinger emerged from his office shouting, “But I need him!”

Staff turnover was high, but many of those who stayed came to admire him for his intellect and his growing list of achievements. Still, they were stunned by his secretiveness. “He was able to give a conspiratorial air to even the most minor of things,” Mr. Eagleburger, who admired him, said before his death in 2011.

Poking fun at himself in a way that some saw as disingenuous, he often told visiting diplomats that “I have not faced such a distinguished audience since dining alone in the Hall of Mirrors at Versailles.”

Nixon had built much of his campaign around the promise to end the war on honorable terms. It was Mr. Kissinger’s task to turn that promise into a reality, and he made clear in a Foreign Affairs article, published as Nixon was preparing to take office, that the United States would not win the war “within a period or with force levels politically acceptable to the American people.”

In the 2018 interview, he said the United States had misunderstood the struggle from the start as “an extension of the Cold War in Europe.”

“I made the same mistake,” he said. “The Cold War was really about saving democratic countries from invasion.” Vietnam was different, a civil war. “What we did not understand at the beginning of the war in Vietnam,” he went on, “is how hard it is to end these civil wars, and how hard it is to get a conclusive agreement in which everyone shares the objective.”

By the time that he and Nixon took office, he argued, it was too late to just leave. “If you come into government and find 550,000 of your troops involved in the battle, how do you end that?” he asked. He and Nixon needed a way out, he said, that did not discredit “the 50,000 dead” or “the people who had relied on America’s word.”

Mr. Kissinger’s pursuit of two goals that were seen as at odds with each other — winding down the war and maintaining American prestige — led him down roads that made him a hypocrite to some and a war criminal to others. He had come to office hoping for a fast breakthrough: “Give us six months,” he told a Quaker group, “and if we haven’t ended the war by then, you can come back and tear down the White House fence.”

But six months later, there were already signs that the strategy for ending the war would both expand and lengthen it. He was convinced that the North Vietnamese would enter serious negotiations only under military pressure. So while he restarted secret peace talks in Paris, he and Nixon escalated and widened the war.

“I can’t believe that a fourth-rate power like North Vietnam doesn’t have a breaking point,” Mr. Kissinger told his staff.

‘War for Peace’

Mr. Kissinger called it “war for peace.” Yet the result was carnage. Mr. Kissinger had an opportunity to end the war in peace talks early in Nixon’s presidency on terms as good as those he ultimately settled for later. Yet he turned it down, and thousands of Americans died because he was convinced he could do better.

As Mr. Kissinger sat with his big yellow legal pads in his White House office, scribbling notes that have now been largely declassified, he designed a three-part plan. It consisted of a cease-fire that would also embrace Laos and Cambodia, which had been sucked into the fighting; simultaneous American and North Vietnamese withdrawals from South Vietnam; and a peace treaty that returned all prisoners of war.

His notes and taped conversations with Nixon are riddled with self-assured declarations that the next escalation of bombing, and a secret incursion into Cambodia, would break the North Vietnamese and force them into real negotiations. But he was also reacting, he later wrote, to a Vietcong and North Vietnamese offensive early in Nixon’s presidency that had killed almost 2,000 Americans and “humiliated the new president.”

Mr. Kissinger later constructed a narrative emphasizing the wisdom of the strategy, but the notes and phone conversations suggest that he had routinely overestimated his negotiating skills and underestimated his opponents’ capacity to wait the Americans out.

It was the bombing campaign in Cambodia — code-named “Operation Menu,” with phases named “Breakfast,” “Lunch” and “Dinner” — that outraged Mr. Kissinger’s critics and fueled books, documentaries and symposiums exploring whether the United States had violated international law by expanding the conflict into a country that was not party to the war. Mr. Kissinger’s rationale was that the North had created supply lines through Cambodia to fuel the war in the South.

Inevitably, reports of the bombing leaked out; it was simply too large an operation to hide. Nixon was certain that the leakers were liberals and Democrats whom Mr. Kissinger had recruited from academia. Thus began Mr. Kissinger’s relationship with J. Edgar Hoover, the powerful director of the Federal Bureau of Investigation. The two began reviewing conversations of Mr. Kissinger’s staff members.

As the internal wars raged in the White House, Le Duc Tho, the North Vietnamese negotiator, dug in. He rejected Mr. Kissinger’s call for a mutual withdrawal of forces; he insisted instead on a full American withdrawal and the formation of a “coalition” government in the South that the North would clearly dominate. Aware that Nixon was beginning to pull troops out, the North’s leadership saw little reason to give way.

It took until January 1973 for Mr. Kissinger to reach a deal, assuring the South Vietnamese that the United States would return if the North violated the accord and invaded. Privately, Mr. Kissinger was all but certain that the South could not hold up under the pressure. He told John D. Erlichman, a top White House aide, that “if they are lucky, they can hold out for a year and a half.”

That proved prescient: Saigon fell in April 1975, with the unconditional surrender of South Vietnam. Fifty-eight thousand Americans and more than three million North and South Vietnamese had died, and eight million tons of bombs had been dropped by the United States. But to Mr. Kissinger, getting it over with was the key to moving on to bigger, and more successful, ventures.

A Door Opens to China

When Mr. Kissinger was writing campaign speeches for Nelson Rockefeller in 1968, he included a passage in which he envisioned “a subtle triangle with Communist China and the Soviet Union.” The strategy, he wrote, would allow the United States to “improve our relations with each as we test the will for peace of both.”

He got a chance to test that thesis the next year. Chinese and Soviet forces had clashed in a border dispute, and in a meeting with Mr. Kissinger, Anatoly F. Dobrynin, the Soviet ambassador to Washington, spoke candidly of the importance of “containing” the Chinese. Nixon directed Mr. Kissinger to make an overture, secretly, to Beijing.

It was a remarkable shift for Nixon. A staunch anti-Communist, he had long had close ties to the so-called China lobby, which opposed the Communist government led by Mao Zedong in Beijing. He also believed that North Vietnam was acting largely as a Chinese satellite in its war against South Vietnam and its American allies.

Nixon and Mr. Kissinger secretly approached Pakistan’s leader, Yahya Khan, to act as a go-between. In December 1970, Pakistan’s ambassador in Washington delivered a message to Mr. Kissinger that had been carried from Islamabad by courier. It was from the Chinese prime minister, Zhou Enlai: A special envoy from President Nixon would be welcome in Beijing.

That led to what became known as Ping-Pong diplomacy. A young member of the American table tennis team playing in a championship tournament in Japan had befriended a Chinese competitor. The Chinese leadership apparently concluded that the American player’s gesture was another signal from Mr. Kissinger. The American team was invited to Beijing, where Mr. Zhou surprised the players by telling them, “You have opened a new chapter in the relations of the American and Chinese people.”

Over the next two months, messages were exchanged concerning a possible presidential visit. Then, on June 2, 1971, Mr. Kissinger received one more communication through the Pakistani connection, this one inviting him to Beijing to prepare for a Nixon visit. Mr. Kissinger pulled Nixon aside from a White House dinner to declare: “This is the most important communication that has come to an American president since the end of World War II.”

The president found a bottle of expensive brandy, and the men toasted their triumph in the same room where, three years later, they would kneel together in agony.

In July 1971, Mr. Kissinger left on what was described as an Asian fact-finding trip. In Pakistan, reporters were told that the secretary was not feeling well and that he would spend a few days at a mountain retreat to recover. A motorcade soon set off for the hills. But it was a decoy; Mr. Kissinger was actually flying to China with three aides.

In Beijing he made a presentation to Mr. Zhou, ending with the observation that as Americans “we find ourselves here in what to us is a land of mystery,” he recalled in a 2014 interview for the Harvard Secretaries of State project. Mr. Zhou interrupted. “There are 900 million of us,” he said, “and it’s not mysterious to us.”

It took three days to work out the details, and after Mr. Kissinger cabled the code word “eureka” to Nixon, the president, without any advance warning, appeared on television to announce what Mr. Kissinger had arranged. His enemies — the Soviets, the North Vietnamese, the Democrats, his liberal critics — were staggered. On Feb. 21, 1972, he became the first American president to visit mainland China.

The Chinese were a little stunned, too. Mao sidelined Mr. Zhou within a month. After that, no Chinese ever mentioned Zhou Enlai again, Mr. Kissinger told the Harvard project. He speculated that Mao had feared that his No. 2 “was getting personally too friendly with me.”

Years later, Mr. Kissinger was more restrained about the achievement.

“That China and the United States would find a way to come together was inevitable given the necessities of the time,” he wrote in “On China,” referring to domestic strife in both countries and a common interest in resisting Soviet advances. But he also insisted that he had not been seeking to isolate Russia as much as to conduct a grand experiment in balance-of-power politics. “Our view,” he wrote, “was that the existence of the triangular relations was in itself a form of pressure on each of them.”

Historians still debate whether that worked. But there is no debating that it made Mr. Kissinger an international celebrity. It also proved vital for reasons that never factored into Mr. Kissinger’s calculus five decades ago — that China would rise as the only true economic, technological and military competitor to the United States.

To Moscow

Nixon’s announcement that he would go to China startled Moscow. Days later, Mr. Dobrynin called on Mr. Kissinger and invited Nixon to meet the Soviet leader, Leonid I. Brezhnev, in the Kremlin. The date was set for May 1972, just three months after the China trip. “To have two Communist powers competing for good relations with us could only benefit the cause of peace,” Mr. Kissinger noted later. “It was the essence of triangular strategy.”

To prepare for the summit, he flew to Moscow, again in secret. Nixon had agreed to let him go on the condition that Mr. Kissinger spend most of his time insisting that the Soviets restrain their North Vietnamese allies, who were mounting an offensive.

By then, however, Mr. Kissinger had changed his mind about how much control the Soviets had over the North Vietnamese, writing to his deputy, Alexander M. Haig, “I do not believe that Moscow is in direct collusion with Hanoi.”

Instead, he sought to reinvigorate negotiations, which had been stumbling along since late 1969, with the aim of limiting the number of ground-based and submarine-launched nuclear missiles that the two countries were pointing at each other and curbing the development of antiballistic missile systems. Mr. Kissinger achieved a breakthrough, writing to Nixon, “You will be able to sign the most important arms control agreement ever concluded.”

That may have been overstatement, but Mr. Brezhnev and Nixon signed what became the SALT I treaty in May 1972. It opened decades of arms-control agreements — SALT, START, New START — that greatly reduced the number of nuclear weapons in the world. The era known as détente had begun. It unraveled only late in Mr. Kissinger’s life. While Mr. Putin and Mr. Biden renewed New START in 2021, once the war in Ukraine started the Russian leader suspended compliance with many parts of the treaty.

Intrigue in Chile

To Mr. Kissinger, there were superpowers and there was everything else, and it was the everything else that got him into trouble.

He never stopped facing questions about the overthrow and death of Mr. Allende in Chile in September 1973 and the rise of Augusto Pinochet, the general who had seized power.

Over the next three decades, as General Pinochet came to be accused — first in Europe, then in Chile — of abductions, murder and human rights violations, Mr. Kissinger was repeatedly linked to clandestine activities that had undermined Mr. Allende, a Marxist, and his democratically elected government. The revelations emerged in declassified documents, lawsuit depositions and journalistic indictments, like Christopher Hitchens’s book “The Trial of Henry Kissinger” (2001), which was made into a documentary film.

The issues harked back to 1970, when Mr. Allende was running for Chile’s presidency. An Allende victory would represent the first by a Marxist in a democratic election, a prospect that concerned Mr. Kissinger.

Nixon, too, was alarmed, according to a White House tape that Peter Kornbluh, of the National Security Archive, cited in his book “The Pinochet File: A Declassified Dossier on Atrocity and Accountability.” It quotes Nixon as ordering the U.S. ambassador in Santiago “to do anything short of a Dominican-type action” to keep Mr. Allende from winning the election. The reference was to the United States invasion of the Dominican Republic in 1965.

Mr. Kissinger insisted, in a memoir and in testimony to Congress, that the United States “had nothing to do” with the military coup that overthrew Mr. Allende. However according to phone records that were declassified in 2004, Mr. Kissinger bragged that “we helped them” by creating the conditions for the coup.

That help included backing a plot to kidnap the commander in chief of Chile’s army, Gen. René Schneider, who had refused C.I.A. entreaties to mount a coup. The general was killed in the attempt. His car was ambushed, and he was fatally shot at point-blank range.

Mr. Kissinger, as national security adviser, presided over the 40 Committee, a secretive body that included the director of Central Intelligence and the chairman of the Joint Chiefs of Staff. All covert actions were subject to the committee’s approval.

In 2001, General Schneider’s two sons filed a civil suit in the United States accusing Mr. Kissinger of helping to orchestrate covert activities in Chile that led to their father’s death. A U.S. federal court, without ruling on Mr. Kissinger’s culpability, dismissed the case, saying that foreign policy was up to the government, not the courts.

Mr. Kissinger, in his defense, said his actions had to be viewed within the context of the Cold War. “I don’t see why we need to stand by and watch a country go Communist due to the irresponsibility of its people,” he said, adding half-jokingly: “The issues are much too important for the Chilean voters to be left to decide for themselves.”

Brutalities and ‘Stability’

Chile was hardly the only place Mr. Kissinger was accused of treating as a minor chess piece in his grand strategies. He and President Ford approved Indonesia’s invasion of East Timor in December 1975, leading to a disastrous 24-year occupation by a U.S.-backed military.

Declassified documents released in 2001 by the National Security Archive indicate that Ford and Mr. Kissinger knew of the invasion plans months in advance and were aware that the use of American arms would violate U.S. law.

“I know what the law is,” Mr. Kissinger was quoted as telling a staff meeting when he got back to Washington. He then asked how it could be in “U.S. national interest” for Americans to “kick the Indonesians in the teeth?”

The columnist Anthony Lewis wrote in The Times, “That was Kissingerian realism: the view that the United States should overlook brutalities by friendly authoritarian regimes because they provided ‘stability.’”

It was a familiar complaint. In 1971, the slaughter in East Pakistan that Nixon and Mr. Kissinger had ignored in deference to Pakistan expanded into a war between Pakistan and India, a nation loathed by both China and the Nixon White House.

“At this point, the recklessness of Nixon and Kissinger only got worse,” Dexter Filkins, of The New Yorker, wrote in discussing Professor Bass’s account in The New York Times Book Review in 2013. “They dispatched ships from the Seventh Fleet into the Bay of Bengal, and even encouraged China to move troops to the Indian border, possibly for an attack — a maneuver that could have provoked the Soviet Union. Fortunately, the leaders of the two Communist countries proved more sober than those in the White House. The war ended quickly, when India crushed the Pakistani Army and East Pakistan declared independence,” becoming the new nation of Bangladesh.

After Washington

Such events led to protests whenever Mr. Kissinger ventured onto college campuses.

So did his consulting ties: When President George W. Bush appointed him to lead a commission to investigate the government’s failures to detect and prevent the terrorist attacks of Sept. 11, 2001, Mr. Kissinger discovered that the appointment required that he disclose his firm’s clients. Rather than comply, Mr. Kissinger abruptly withdrew, saying he could not serve if it meant revealing his clients.

While Mr. Kissinger worked hard to shape the history of his own decisions, he found himself in the odd position of living so long that his own memorandums were declassified while he was still on the world stage. In 2004, responding to Freedom of Information requests, the State Department released thousands of pages of transcripts of Mr. Kissinger’s telephone calls during the Nixon administration. Some revealed chummy conversations with Washington journalists; others showed a president who in the midst of Watergate was too drunk to talk to the British prime minister.

Still more declassified documents revealed how Mr. Kissinger had used his historic 1971 meeting with Mr. Zhou in China to lay out a radical shift in American policy toward Taiwan. Under the plan, the United States would have essentially abandoned its support for the anticommunist Nationalists in Taiwan in exchange for China’s help in ending the war in Vietnam. The account contradicted one he had included in his published memoirs.

The emerging material also revealed the price of an American-interests-first realism. In tapes released by the Nixon Presidential Library and Museum in 2010, Mr. Kissinger is heard telling Nixon in 1973 that helping Soviet Jews emigrate and thus escape oppression by a totalitarian regime was “not an objective of American foreign policy.”

“And if they put Jews into gas chambers in the Soviet Union,” he added, “it is not an American concern. Maybe a humanitarian concern.”

The American Jewish Committee described the remarks as “truly chilling,” but suggested that antisemitism in the Nixon White House may have partly been to blame.

“Perhaps Kissinger felt that, as a Jew, he had to go the extra mile to prove to the president that there was no question as to where his loyalties lay,” David Harris, the committee’s executive director, said.

Mr. Kissinger is survived by his wife, Ms. Maginnes, and his children with Ms. Fleischer, David and Elizabeth. His younger brother, Walter B. Kissinger, a former chairman of the multinational company the Allen Group, died in 2021. Mr. Kissinger’s final book, “Leadership: Six Studies in World Strategy,” was published in 2022.

Mr. Kissinger was aware of his contentious place in American history, and he may have had his own standing in mind when, in 2006, he wrote about Dean Acheson, secretary of state under Truman, in The Times Book Review, calling him “perhaps the most vilified secretary of state in modern American history.”

“History has treated Acheson more kindly,” Mr. Kissinger wrote. “Accolades for him have become bipartisan.”

Thirty-five years after his death, he said, Acheson had “achieved iconic status.”

Mr. Kissinger clearly became an icon of a different kind. And he was acutely aware that the challenges facing the nation had changed. At age 96, he plunged into questions surrounding artificial intelligence, teaming up with Eric Schmidt, Google’s former chief executive, and the computer scientist Daniel Huttenlocher to write “The Age of AI: And Our Human Future” (2019), in which he discussed how the development of weapons controlled by algorithms, rather than directly by humans, would change concepts of deterrence.

After donating his papers to Yale, Mr. Kissinger reconciled with Harvard — the institution where he had made his name — but he made clear that he had not been welcomed back after Vietnam.

Mr. Allison, the Harvard professor, and Drew Faust, the university’s president at the time, were determined to heal the wound. Mr. Kissinger was enticed to return for a talk in which he was interviewed by a graduate student; a dinner at the president’s house followed. “I would not have guessed I would be back inside these walls,” he said.

One student asked him about his legacy. “You know, when I was young, I used to think of people of my age as a different species,” he said to laughter. “And I thought my grandparents had been put into the world at the age at which I experienced them.”

“Now that I’ve reached beyond their age,” he added, “I’m not worried about my legacy. And I don’t give really any thought to it, because things are so changeable. You can only do the best you’re able to do, and that’s more what I judge myself by — whether I’ve lived up to my values, whatever their quality, and to my opportunities.”