Dick Garwin Fought Nuclear Armageddon. He Hid a 50-Year Secret.

Enrico Fermi’s battle with cancer was nearing its end in late 1954 when he received a visitor.

Fermi, a Nobel laureate in physics, had fled fascism in Europe and become a founder of the nuclear age, helping bring the world’s first reactor and first atom bomb to life.

The visitor, Richard L. Garwin, had been Fermi’s student at the University of Chicago, the laureate calling him “the only true genius I have ever met.” Now, he had done something known at the time only by Fermi and a handful of other experts. Not even his family knew. Three years earlier, the boy wonder, then 23, had designed the world’s first hydrogen bomb, which brought the fury of the stars to Earth.

In a test, it had exploded with a force nearly 1,000 times as powerful as the atomic bomb that leveled Hiroshima, its power greater than all the explosives used in World War II.

To his reverential student, Fermi confided a regret. He felt his life had involved too little participation in crucial issues of public policy. He died a few weeks later at 53.

After that visit, Dr. Garwin set out on a new path, seeing nuclear scientists as having a responsibility to speak out. His resolve, he later told a historian, came from a desire to honor the memory of the scientist he had known best and admired most.

“I modeled myself to whatever extent I could after Fermi,” he said.

Dr. Garwin, the designer of the world’s deadliest weapon, died last Tuesday at age 97, leaving behind a legacy of nuclear horrors he devoted his life to countering. But he also left a strange puzzle.

Why for a half-century did he hide what Fermi and a dozen presidents knew? It was a topic I discussed with him this January in an interview, the last of many.

The riddle is especially odd because his central role in creating the H-bomb became the motivating force that drove him forward, that helped him turn Fermi’s regrets into a life of political and social activism, that made him an inconspicuous giant of nuclear arms control.

“If I could wave a wand” to make the H-bomb vanish, he once told me, “I would.”

In a blinding flash, the atomic bomb dropped on Hiroshima by the Enola Gay killed at least 70,000 people. Deadly like no earlier weapon, it was still quite limited in contrast with Dr. Garwin’s superweapon. One proposed version had the force of more than 600,000 Hiroshimas. The mind boggles at such numbers. Even so, Cold War analysts coolly judged that it could reduce a region the size of France to ashes. His weapon was a planet shaker. It could end civilization.

That bomb wasn’t the only feat driven by Dr. Garwin’s prodigious intellect. He made basic discoveries about the structure of the universe, laid the groundwork for wonders of health care and computers, and won many awards. He pushed back frontiers in astronomy, physics, superconductors, orbital reconnaissance and a multitude of other topics he investigated, often at the U.S. government’s behest.

But what drove him, what made him eager to advise presidents, was not his gift for coming up with marvels of discovery and innovation but, courtesy of Fermi, a personal crusade to save the world from his own creation.

Henry A. Kissinger advised at least 12 American presidents in some capacity. Dr. Garwin never officially joined any president’s cabinet, as Kissinger had. But in our last interview, the physicist looked over a list of presidents and one by one identified the commanders-in-chief he had counseled. There were 13.

While eager to counter his brainchild, Dr. Garwin took no personal or moral responsibility for bringing the H-bomb into existence. Its birth, he argued, was inevitable.

“Maybe I sped up its development by a year or two,” he said in 2021. “That’s all.” Historians of the age tend to agree. The Soviet Union quickly followed his pioneering lead, then a half-dozen other nations. Today, hydrogen bombs have replaced atom bombs in most arsenals, creating a world of uneasy standoffs among nuclear foes.

By all accounts, Dr. Garwin believed that he — and sometimes he alone — could peer into the chaos of the universe and discern its underlying order. Like J. Robert Oppenheimer, who during World War II led the making of the first atomic bomb, he could also be cruel and intolerant of those he saw as less gifted.

Even so, Dr. Garwin showed a knack for teamwork and generosity with peers he respected. Over decades, the physicist worked hard to advance the hunt for gravitational waves — ripples in the fabric of space-time that Einstein predicted. He supported the construction of costly detectors, which, in 2015, successfully observed the ripples, opening a new window on the universe. Dr. Garwin beamed with pride when the finding won a Nobel Prize.

So too, Dr. Garwin managed to walk a tricky path through the nation’s military-industrial complex, which crushed Oppenheimer and coddled Edward Teller, an early proponent of hydrogen bomb research. For decades, he criticized the complex from within, promoting some ideas and undermining others, using his intellect and standing as a knowledgeable insider to shake things up — often anonymously.

“The most influential scientist you’ve never heard of” is how his biographer cast him. The physicist told newcomers to the federal apparatus that they could get something done or get credit, but not both. He was, in some respects, the antithesis of Kissinger, who carefully tended his public image.

The left loved Dr. Garwin’s attacks on the American military establishment, but his own compass seemed to align less with politics than pragmatism. He received awards from President George W. Bush, a Republican, as well as President Barack Obama, a Democrat.

“He’s never met a problem he didn’t want to solve,” Mr. Obama said in 2016 when he presented Dr. Garwin with the Presidential Medal of Freedom, the nation’s highest civilian honor. The two-term president described the physicist as advising White House occupants “rather bluntly.”

Overall, Dr. Garwin’s life can be seen as a tale of genius in which key manifestations were obscured by a wall of silence. Why, for instance, did he wait so long to tell his family about his H-bomb role? Was he trying to protect his loved ones from criticism and hateful bluster?

No. It turned out that, as can happen in lives of government service, he felt that sensitive issues of national security loomed over him.

In our last interview, Dr. Garwin said he worried that talkative family members might inadvertently bring him to the attention of foreign intelligence agencies eager to learn H-bomb secrets. That concern, he added, haunted him even after his role became known publicly.

“I still worry about that,” he said at his home in Scarsdale, N.Y., on a cloudy winter day. He glanced out the window.

“They could be listening now.”

ADVISING THE ADVISERS

The Birth of the Hydrogen Bomb

Richard Lawrence Garwin was born in Cleveland on April 19, 1928. His father taught electronics at a technical high school.

As a child, Richard, called Dick, impressed adults with his language and math abilities. He loved to take apart and reassemble things, including a vacuum cleaner.

Despite his obvious talents and his early entry into high school, an English teacher there told his parents that Dick would never get into college. He defied that prediction, studying physics at the Case School of Applied Science, in Cleveland. The teen lived at home, took the bus to school and worked nights.

He graduated at 19 and Standard Oil offered him a full ride for graduate study at the University of Chicago, which had one of the nation’s top physics departments.

Fermi became the young man’s adviser. Two years later, in 1949, Dr. Garwin graduated from Chicago with a doctorate in physics and became an instructor at the school.

The 21-year-old had been too young to play a role in the Manhattan Project, but now found himself deeply involved in what followed.

Like many Americans, Dr. Garwin grew concerned when Moscow that summer detonated its first atom bomb. How would Washington respond? In early 1950, President Harry S. Truman announced that the nation would seek to make “the so-called hydrogen or superbomb.”

Fermi invited Dr. Garwin to join him at Los Alamos, the base set amid the tall pines and deep canyons of New Mexico’s backcountry where Oppenheimer’s bomb was born. Now on the agenda for the sprawling lab: trying to make good on Truman’s threat.

Deep inside every star, extraordinarily high heats and pressures fuse hydrogen atoms into helium, releasing bursts of energy. The Los Alamos idea was to mimic that fusion process. The experts called it thermonuclear — in part to distinguish its high-temperature reactions from those of atomic bombs, which start at room temperature.

The general plan was that an exploding atom bomb would act as a match to ignite the hydrogen fuel. The question was how. Early ideas had atomic and hydrogen fuels layered in alternating bands, similar to the insides of a baseball.

The breakthrough came in early 1951. Teller and Stanislaw Ulam, a Los Alamos colleague, envisioned two distinct stages set next to each other inside a cylindrical casing.

Moving at the speed of light, radiation from the exploding atom bomb would hit the casing’s inner wall and, in a rebound, flood the interior with a colossal burst of rays that would compress and ignite the hydrogen fuel.

The new idea gave the bomb unlimited power. Because the hydrogen fuel was separate from the initial mayhem of atomic debris and shock waves, it could, in theory, be infinitely large.

Teller asked Dr. Garwin to draw up a detailed plan. He warned that it would have to address “every conceivable doubt” of top scientists. “Garwin’s paper was criticized up and down,” Teller wrote in his memoirs, but the young man’s plan “remained unchanged.”

The prodigy turned the rough idea into a four-page plan that’s still classified top secret. He attached a large schematic diagram.

On a coral atoll in the Western Pacific, the device grew slowly. Dr. Garwin never visited the test site where his finished creation stood two stories high and weighed 82 tons.

The test blast, code-named Ivy Mike, took place on Nov. 1, 1952. It vaporized a Pacific isle and produced a mushroom cloud 100 miles wide.

Dr. Garwin, then 24, kept his head down. No news accounts cited his name. No one condemned or praised him. He was an assistant professor of physics at the University of Chicago, not a high government official or a scientific celebrity.

A month after the blast, he joined the International Business Machines Corporation, which allowed him to hold a physics post at Columbia University. In the decades to come, he was granted 47 patents for his IBM work.

The unusual arrangement also gave him the freedom to repeatedly change the course of history. Dr. Garwin did so mainly by offering scientific counsel to presidents and their advisers — a continuum of White House consulting that ran from Eisenhower to Trump.

ADVISING KENNEDY

The Abolition of an H-bomb Threat

President John F. Kennedy used the nation’s scientific and military feats to spook Moscow and showcase the West’s technological edge. It was his top Cold War strategy.

Then disaster struck.

In a case of bad things having good outcomes, the repercussions of the disaster helped give birth to the first successful instance of nuclear arms control.

The crisis began on July 9, 1962, when the American military, seeking ways to destroy incoming Soviet warheads, detonated an H-bomb some 250 miles above the Pacific Ocean. The record height for a thermonuclear blast produced surprises both on the ground and in space. Streetlights in Hawaii went out. Satellites in orbit failed.

It turned out the blast had pumped up the radiation belts around Earth, making the doughnut-like rings of energetic particles more dangerous. The military was planning an even higher-altitude detonation that summer — more than 800 miles up.

Kennedy wanted to quickly assess the risks. Pressed by the Pentagon, he had already approved preparations for that extremely high blast, code-named Urraca. The president’s urgent question was whether the detonation of U.S. nuclear arms in outer space could produce enough radiation to poison humans and ruin his announced plan to land astronauts on the moon.

On July 25, 1962, he sent Dr. Garwin a telegram, inviting him to join his White House science advisory team.

Weeks later, Kennedy met with Dr. Garwin and senior advisers in the Oval Office to discuss the radiation dangers. The physicist recalled the president fearing that the recent blast “had killed the Apollo program,” which was working to put Americans on the moon. How long would the enhanced radiation last?

“A long time,” Dr. Garwin replied, adding that exactly how long was impossible to say. After some discussion of the risks and uncertainties, Dr. Garwin suggested that the danger zone might persist anywhere from two to 20 years.

That Oval Office meeting was, in all likelihood, a turning point.

On Sept. 5, 1962, Kennedy asked his national security and science advisers if the radiation hazard could “make a lunar journey prohibitive.” They discussed the risks, the lineup of impending American nuclear tests and whether the military could live without the 800-mile-high Urraca detonation.

At a National Security Council meeting two days later, the high-altitude test was canceled.

The next year, Kennedy signed a treaty with the Soviet Union that banned nuclear tests in outer space, in the atmosphere and under water. The weapons could be tested only deep underground. Slowly, the heightened radiation levels in the planetary belts declined through the natural process of nuclear decay.

From 1968 through 1972, NASA sent two dozen Apollo astronauts hurtling through the danger zones. Afterward, experts studying the crews’ exposures found that their doses were less than those of workers who held industrial jobs involving radiation. The astronauts suffered no debilitating health effects.

ADVISING NIXON

A Leap in H-bomb Surveillance

President Richard M. Nixon wanted Moscow and Washington to sign a historic pact to limit their nuclear arms.

Formal talks began in 1969, the year he took office. In parallel, the president and his advisers sought ways to better assess the size of the Soviet arsenal and thus verify compliance with any accord. The overall aim was to make the balance of nuclear terror — the threat of mutually assured destruction — more stable, and a stronger deterrent to war.

A new generation of spy satellites would be a central tool. High above the Earth, they would open a new lens on the secretive movements of Soviet bombers, submarines and missiles capable of hurling thermonuclear arms at the United States. Dr. Garwin, already one of President Nixon’s science advisers, threw himself into the satellite effort.

The nation’s early spy satellites, which relied on photographic film, were slow, clumsy and wasteful. It could take weeks for exposed film to get to photo analysts. And the costly orbiters, once out of film, went into the celestial junkyard.

Dr. Garwin led a team of experts who foresaw a more advanced type of spacecraft that would replace film with microelectronics and radio transmitters. Fresh images would flash to Earth. The team also called for powerful new telescopes. In effect, the spy craft were to be precursors to the Hubble Space Telescope, but aimed at the Earth.

Even by the usual standards of federal secrecy, the satellite project was extremely hush-hush. In July 1971, Dr. Garwin had drafts of the final report delivered by a special class of courier to members of his team. They were required to read them, return them and keep no copies.

The next month, Dr. Garwin and a colleague briefed Kissinger, who backed the new electrooptical approach. Remarkably, the innovation was decades ahead of the shift in consumer cameras from film to digital.

That September, President Nixon approved a plan to develop the new spy satellite, which became the archetype for all that followed. For East-West relations, the technology was seen as raising predictability and lessening surprise, thus lowering tensions between the superpowers.

The next year, Nixon met in Moscow with the Soviet leader Leonid I. Brezhnev to sign an accord that, for the first time, limited their nuclear arsenals.

Dr. Garwin received two awards for this work, one from the C.I.A. in 1996, and another in 2000 from the National Reconnaissance Office, which runs the satellite fleets.

That office’s citation said the physicist had helped Kissinger “understand the critical role” the spy technology would come to play in national security — in stabilizing the uneasy standoff between foes armed with the deadliest of weapons.

ADVISING CLINTON

The Push to End H-bomb Testing

Simplicity made the Hiroshima bomb a sure thing. It had no test explosion. H-bombs were tricker. By definition, they needed multiple tests to uncover flaws and optimize results.

For decades, Dr. Garwin’s push for a comprehensive ban on test detonations rested primarily on that fact — no testing, no H-bomb. Though he saw Kennedy’s space ban as a good start, he wanted to head off not only new arms races, but also new states aspiring to the world’s most destructive weapons.

The end of the Cold War seemed like the moment. In 1993, President Bill Clinton announced plans for a treaty in which all nations would forgo all nuclear blasts, as Washington was doing unilaterally. This meant banning tests even underground, the last permissible zone.

In 1993, Dr. Garwin became chair of the Arms Control and Nonproliferation Advisory Board in the State Department, which guided senior federal officials, including in the White House. It also helped build public support for a test-ban agreement.

Crucially, in August 1995, Dr. Garwin helped resolve a technical dispute that was threatening to become a deal-breaker in the treaty negotiations. It centered on whether a ban should allow minuscule blasts. He addressed it as a longtime member of the Jasons, a secretive group of independent federal science advisers. In a lengthy report, the group backed the comprehensive ban, saying the United States could sign a treaty even if it ruled out minute tests.

Days later, Mr. Clinton echoed that finding in announcing that he would seek what experts called a zero-yield treaty. “I hope,” he said, “it will lead to an early consensus” at the negotiating table.

Instead, the talks dragged on. And France and China rushed to do last-minute detonations before any ban took effect.

Finally, in September 1996, a solemn procession of world government representatives, including Mr. Clinton, signed the Comprehensive Test Ban Treaty.

Then things fell apart.

Mr. Clinton won re-election that November but now faced Republican majorities in both the House and the Senate.

Worse, the president’s dalliance with Monica Lewinsky, an intern, came to light in early 1998, fueling a political firestorm that crippled the White House.

As Senate Republicans raced for a quick treaty vote, Dr. Garwin testified before the Foreign Relations Committee.

“We are better off,” he argued, “with a test ban than without it.”

Six days later, on Oct. 13, 1999, the Senate rejected the treaty. Though eventually signed by 187 nations, the treaty never entered into force because the United States and a handful of other key players failed to ratify it.

Still, Dr. Garwin and his colleagues had created a new global norm. The long, hard process of hammering out a global consensus on the merits of a ban, embraced by thermonuclear states, led to a more stable new era. Gone were the shock waves that had radiated from underground test sites and ricocheted around the globe. Since then, the United States and other main nuclear powers have tested no weapons. Now there’s a new kind of silence.

“You do these things,” Dr. Garwin told me shortly after the Senate rejected the treaty. “And if you keep at it for a long time, sometimes you win.”

ADVISING HIMSELF

The Public Debut of the H-Bomb Designer

In 1979, Edward Teller suffered a heart attack and so discovered, as he told a friend, “that I am not immortal.” While recovering, he shared his recollections on the making of the hydrogen bomb with that friend, who had brought along a tape recorder.

“So that first design,” Teller said, “was made by Dick Garwin.” He repeated the tribute to avoid any misunderstanding.

For 22 years, that recording was lost to history. By chance, it also fit nicely with Dr. Garwin’s own determination to hide his H-bomb role.

Myths spread. In 1995, “Dark Sun,” a 700-page account of the hydrogen bomb’s making, attributed its design to a committee of elder scientists. It made no mention of the Cleveland upstart.

That changed in April 2001. George A. Keyworth II, Teller’s friend, who later served as President Ronald Reagan’s science adviser, gave me a transcript of the tape recording and I wrote about it for The New York Times. It was noticed, including by Dr. Garwin and his family.

Though Teller had previously acknowledged the young physicist’s role, those mentions were buried in specialist writings and meetings. Now, suddenly — a half-century after the fact — Dr. Garwin gained wide public recognition as the H-bomb’s designer.

“That was when people really knew,” Lois, his wife, told a historian. “And people who knew Dick very, very well, and had known him for a very long time, expressed real surprise.”

After that, as much as ever, he raced ahead. The polymath lectured and wrote papers on space weapons, land mines, terrorism, pandemics, submarines, science advising, food aid programs, automatic teller machines, Iran’s nuclear ambitions, the nation’s electrical grid, the disposal of radioactive waste, catastrophic risks and nuclear disarmament. The last entry in his comprehensive archive is dated early this year.

Around that time, I decided that the elder statesman of nuclear arms control, like Teller, was probably not going to live forever. He was 96. I had some questions.

During that interview, to my surprise, Dr. Garwin said Fermi had emphasized the wrong danger in once calling the H-bomb “an evil thing” because of its unlimited destructiveness.

“That’s not the threat,” he said. The great danger, he added, is “so many nuclear weapons,” which raise the risk of theft, missteps, accidents, unauthorized use — and the world falling from mutual deterrence into a thermonuclear abyss.

To me, that last visit with Dr. Garwin was another glimpse of a bygone era in which he struggled inconspicuously to counter an existential threat to humankind.

I asked if he had ever considered a memoir.

“I tried,” said the man known for his blunt honesty. “It’s an impossible job.”