A treasure of finely woven secrets and insights lies in Daniel Ellsberg’s new memoir, The Doomsday Machine: Confessions of a Nuclear War Planner. Their importance grows each day that the nuclear stand-offs on the Korean Peninsula, in South Asia and between the United States and Russia go unabated. People interested in international affairs who are of a certain age know who Daniel Ellsberg is, but the younger cohort of nuclear policy makers, scholars, and pundits grows every year, and will gain by knowing the riches Ellsberg offers.

The new Steven Spielberg movie, The Post, may help elicit interest—Ellsberg features centrally in the movie. He is the man who, as a Defense Department consultant, stole and copied the mammoth super-secret Pentagon Papers and released them to the New York Times, the Washington Post and other papers. These papers exposed the duplicitous failure of US policies and actions in Vietnam and led President Richard Nixon’s henchmen to take actions against Ellsberg that, ultimately, became part of Nixon’s undoing. Thereafter, Ellsberg became one of the world’s most famous anti-war and human rights and governmental transparency activists.

Ellsberg got immersed in the Vietnam War and the Pentagon Papers and was a highly placed, hyper-inquisitive nuclear war planner. In 1959 and 1960, he traveled to far-flung airbases, naval ports and ships to interview the men who actually would (or would not) implement their president’s intentions regarding nuclear war. When the new administration of President John Kennedy arrived, Ellsberg directly shaped the early effort to reform the nuclear plans inherited from the Eisenhower administration. During the Cuban Missile Crisis in 1962, Ellsberg, then only 31 years old, staffed two round-the-clock working groups advising the State Department and Defense Department. Two years later, he conducted the Pentagon’s higher-than-top-secret study of the Crisis.

Ellsberg copied the notes he took during these projects and some of the related government documents at the same time as he copied the Pentagon Papers in 1969. He intended to release both sets of papers to the public, hoping to stop the war in Vietnam and the civilisation-threatening US-Soviet nuclear arms race. When he went underground to elude the government’s pursuit following the publication of the Pentagon Papers, he gave the nuclear papers to his brother to hide. But the river near where Ellsberg’s brother had buried the cache flooded and the documents were swept away, never to be found. (Ellsberg guesses they are lying under the thick concrete foundation of an apartment building that was constructed not long after the flood).

The book is an easy, fast-paced read. Ellsberg is a good story teller, the material is riveting and the nuclear practices and debates he presents are still pertinent today, especially in the newest nuclear-armed states—India, Pakistan and North Korea.

For example, the raw intelligence data and assessments that leaders are given about adversaries’ military capabilities, intentions and perceptions of one’s own capabilities and intentions are often incorrect. Ellsberg drives this home by recounting the Cuban Missile Crisis and what he learned about it afterward.

President Kennedy’s military advisors were pushing him hard to conduct massive air strikes and then invade Cuba, to force the Soviet Union to remove the nuclear-capable ballistic missiles it was deploying and to remove Fidel Castro from power. But, US officials did not know that the Soviets already had deployed tactical nuclear weapons on the island, and that the local Soviet commanding general had been authorised to use them to stop an American invasion. Kennedy was told that 8,000 Soviet military personnel were on the island to defend against an invasion; the actual number was more than 42,000. US officials did not know that Soviet Foxtrot submarines contained nuclear-tipped torpedoes, and that when American ships dropped practice depth charges on these submarines believing the Soviet crews understood this to be a pre-arranged signal that they should surface, the Soviet crews thought they were under attack and prepared to use their nuclear weapons.

Today, US officials in candid moments admit they do not know a great deal about North Korea’s nuclear and other military capabilities, or about how the North Korean leadership and armed forces would behave in a conflict.

Speaking of North Korea (or of India and Pakistan), the policies and procedures that military forces follow in drills and exercises with nuclear weapons may have unintended dangerous consequences in actual war time conditions. Ellsberg discovered this problem during a 1960 visit to the Kadena US Air Force base on Okinawa. If planes laden with nuclear bombs were to practice taking off in rapid succession, there would be risks of crashes that could cause partial detonations of weapons and radioactive contamination. Thus, “in these practice alerts,” Ellsberg recalls, “the pilots would jump into their planes and gun up their engines. But they didn’t go to the point of racing down the runway…let alone taking off.” Ellsberg conjectured that if the pilots were ever ordered actually to take off with their nuclear weapons, this “would almost surely lead them to infer that ‘this was it’. An enemy attack was underway or else they were leading a preemptive attack.” Pilots would then be in a “state of mind that they would head for their rendezvous areas, even if they received no” order to execute attacks.

This possibility was especially worrisome for at least two reasons. At that time, Ellsberg discovered, US nuclear procedures did not include pre-planned orders to be conveyed to forces not to execute their attack orders. And, due to atmospheric conditions in the Pacific region, radio communications often were interrupted for extended periods. Thus, pilots flying toward targets would not necessarily, or even probably, be able to learn that they were doing so under false alarm or that circumstances had changed and they should not proceed to drop their weapons on their targets. Ellsberg asked a commander of a nuclear air squadron based near the demilitarised zone between North and South Korea what he thought his pilots would do in such a situation. The commander surmised that if one pilot proceeded on to his target, the others would do the same. Political leaders in Washington had no inkling of any of this.

Thirty-nine years later, Indian pilots carrying conventional munitions during the Kargil conflict with Pakistan had a pertinently similar experience. As Sushant Singh reported in the Indian Express last year, on June 24, 1999, an Indian Air Force Jaguar flying over the Line of Control laser targeted a forward base of the Pakistan Army. However, the pilot of a second Jaguar, which was following closely behind and was supposed to fire the bomb, directed his weapon instead to hit on the Indian side of the LoC, at the instruction of a superior flying nearby, who had a doubt whether they had crossed the LoC. The superior officer was dubious in part because he knew the flight commander “was excitable and known for his impetuousness.” None of the pilots then knew that Pakistan Prime Minister Nawaz Sharif and Army Chief of Staff General Pervez Musharraf were attending a large meeting at the targeted base, which was later confirmed by checking video. It is not difficult to imagine the consequences if the second pilot had executed the strike and killed Pakistan’s leaders.

Another story Ellsberg tells may also have relevance in other countries today. In the Spring of 1961, President Kennedy’s National Security Advisor, McGeorge Bundy, had asked the director of the military’s Joint Staff to send to the White House a copy of the super-secret Joint Strategies Capabilities Plan—the US nuclear war plan. The director of the Joint Staff told Bundy “we can’t release that.”

“’Bundy said, ‘The president wants to read it.’

“The director said, ‘But we’ve never released that. I can’t.’”

“Bundy told him, ‘You don’t seem to be hearing me. It’s the president who wants it.’”

“‘We’ll brief him on it.’”

“Bundy said, ‘The president is a great reader. He wants to read it.”

Eventually, it was agreed that Bundy and Secretary of Defence Robert McNamara would be briefed on the plan at the Pentagon. But, as Ellsberg recounts in delicious detail, what these top officials representing the president were shown was a “Briefing on the JSCP,” not the actual plan itself. Not long after, Ellsberg, who had seen the actual plan, compared it with what was shown Kennedy’s representatives. He noticed a number of important discrepancies, all of which understated the devastation that would result from execution of the actual nuclear war plan.

Does the prime minister of India (or his national security advisor) know the actual details and implications of India’s nuclear weapons operation plans? Does anyone think that Donald Trump knows and understands US nuclear war plans? What about other heads of nuclear-armed states?

The issue that seizes Ellsberg today is nuclear winter. Since the 1980s when the potential phenomenon was first identified, atmospheric scientists have concluded that the dust, smoke and soot produced by the blast and firestorms caused by detonating 100 nuclear weapons in South Asia or other possible target zones would probably rise into the stratosphere and encircle the globe. This would create a blanket that would block most sunlight around the earth for five to ten years and deplete global ozone at unprecedented levels. According to a study by eminent climatologists in 2017, this would “cause an unprecedented loss of food, exhausting the global food storage in one year, and could not be made up, since the loss would continue for a decade.” Of course, thankfully, no one has conducted an experiment that would prove or disprove the models, just like no one has conducted a related experiment to see if nuclear war could be kept limited.

Indians and Pakistanis are not alone in avoiding discussion and reckoning with the prospect of nuclear winter and its implications. Practically no one in official or expert circles in the US, Russia and China talks about it or factors it into the countless policy debates over nuclear weapons and operational policies. Ellsberg, along with many atmospheric scientists, argues that the science is plausible enough, that every government possessing these weapons should be asked how their nuclear arsenals and war plans can be justified in light of the risk of nuclear winter.

Ellsberg closes by suggesting a number of steps that the US and Russia could, or should, take to reduce the size of their nuclear arsenals and their salience in military doctrine and planning. He also pleads with Indians and Pakistanis to recognise and act upon the dangers of nuclear winter that even their relatively small nuclear arsenals would pose if they were detonated on the two countries’ large and combustible cities. The US and Russia started the global nuclear competition unaware of the possibly suicidal environmental effects that even “winners” of nuclear war would experience. Doomsday machine indeed.

This book review was originally published in The Wire