Nuclear Weapons-12

Nearly 700 scientists and engineers, including 21 Nobel laureates, asked President Biden on December 15 to use his forthcoming declaration of a new national strategy for managing nuclear weapons as a chance to cut the U.S. arsenal by a third, and to declare, for the first time, that the United States would never be the first to use nuclear weapons in a conflict. The letter to Mr. Biden also urged him to change, for the first time since President Harry S. Truman ordered the dropping of the atomic bomb over Hiroshima, the American practice that gives the commander in chief sole authority to order the use of nuclear weapons. The issue gained prominence during the Trump administration, and the authors of the letter urged Mr. Biden to make the change as “an important safeguard against a possible future president who is unstable or who orders a reckless attack.”

But while Mr. Biden has often declared that he will be guided by scientific advice alone when it comes to managing the Covid-19 pandemic, he has made no such pledge in the nuclear arena, where strategists, allies protected by the American nuclear umbrella, and members of Congress all have views — many of them diametrically opposed to the ones described by scientists.

Among the authors of the letter are numerous members of the National Academy of Sciences and the Union of Concerned Scientists. They include Barry Barish of the University of California, Riverside; Jerome I. Friedman of the Massachusetts Institute of Technology; John C. Mather of the University of Maryland; and Sheldon L. Glashow of Harvard, who have all been awarded the Nobel Prize in Physics; and Richard L. Garwin, a nuclear expert and recipient of the Presidential Medal of Freedom, who has advised a series of presidents. They were motivated by the coming publication of the Nuclear Posture Review, a document each new president usually issues in the first year or two of his term. Mr. Biden’s is expected early in 2022, though the internal debate over its contents has been very closely held.

The letter noted Mr. Biden’s own words in 2017, as he was considering his run for president, when he said that “it’s hard to envision a plausible scenario in which the first use of nuclear weapons by the United States would be necessary or make sense.” During the campaign, he said the “sole purpose” of the American arsenal “should be deterring — and if necessary, retaliating against — a nuclear attack.” The letter argued that “by making clear that the United States will never start a nuclear war, it reduces the likelihood that a conflict or crisis will escalate to nuclear war.” And it would demonstrate, they argued, that the United States was committed to the Nuclear Non-proliferation Treaty, which obliges the nuclear-armed states to move toward reducing their arsenals.

President Obama balked at making the commitment, even while he declared that nuclear weapons would no longer be at the center of American defense policy. And in recent months American allies — including Japan, the target of that first attack — have argued quietly against a “no first use” declaration, saying that it would make them more vulnerable to a crippling, non-nuclear attack, including a cyberattack or conventional attack that could take out their electrical grids and their water and fuel lines.

While the administration has not said how the new nuclear weapons strategy will be different from that of former President Donald Trump, some language echoing Mr. Biden’s carefully chosen term about the “sole purpose” of nuclear weapons seems likely. But that stops short of committing never to use a weapon first.

“The review will take account of the current security environment and will assess U.S. strategy, posture, and policy,” the White House’s National Security Council said in a statement. “The U.S. will continue to maintain a safe, secure, and effective strategic deterrent while ensuring our extended deterrence commitments to allies and partners remains strong and credible.”

A number of members of the House and Senate serving on national-security related committees have worried that at a time when China is expanding its arsenal and Russia is threatening former Soviet states that have joined NATO, a no-first-use pledge might give the appearance of weakness. “No-first-use is feel-good foreign policy,’’ Richard Haass, the president of the Council on Foreign Relations, said. “Our enemies wouldn’t take the commitment seriously. And it would undermine the confidence of our friends.”

The scientists and engineers also argued for a commitment by Mr. Biden to reduce the arsenal to “fewer than 1,000 deployed missile warheads and bombers,” though they did not say by when. “These reductions will increase U.S. national security,’’ they argued, because it “will slow the spiraling nuclear arms race with Russia and China,” and help fulfill America’s treaty obligation “to take steps toward disarmament.”

But as a political matter, it is almost unimaginable that Mr. Biden would reduce the arsenal to that level without an agreement by Russia to do the same. When he came to office, Mr. Biden renewed for five years the New Start agreement, which limits the arsenal to 1,550 long-range strategic weapons; currently the United States arsenal appears to be below that limit.

But in recent months, the revelation that China is building what appear to be new missile silos, and testing potential delivery vehicles for hypersonic weapons that avoid traditional missile defenses, has led some Pentagon officials to call for funding for new classes of weapons that can deliver nuclear warheads, including hypersonic vehicles.

China has said repeatedly in recent months that it has no intention of entering arms control talks with the United States, noting that its arsenal is five times smaller than Washington’s.

The scientists’ letter also urges Mr. Biden to cancel the program to replace the silo-based intercontinental ballistic missiles that dot the American West. Under current plans, the United States will replace those aging missiles starting in 2029, at a cost of at least $100 billion; the letter calls for Mr. Biden to simply extend the lifetime of the current arsenal, and ultimately consider eliminating silo-based missiles. Advocates of that position argue they are the most vulnerable to attack, and are the weapons that are most likely to be launched first — perhaps in response to a false alarm.

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The Biden administration is considering killing off several nuclear weapon programs that were greenlit by the Trump White House, as an internal debate over the nation’s nuclear arsenal enters its final phase. According to nine current and former officials with knowledge of the deliberations, the Nuclear Posture Review is not expected to make major changes to nuclear weapon policy. Nor is it likely to recommend deep cuts to multibillion-dollar plans to build new intercontinental ballistic missiles, nuclear-armed submarines and stealth bombers, they said.

But national security officials are debating whether to jettison a new nuclear-armed cruise missile now in the research phase, retire a Cold War-era thermonuclear bomb, and possibly even remove a new “low-yield” warhead that the previous administration deployed on submarines, the current and former officials said. Such changes would fall short of the overhaul of nuclear policy and programs that President Joe Biden has long argued would help blunt a nuclear arms race, namely a declaration that the United States would not be the first to strike an adversary using nuclear weapons.

Yet halting the Trump-era “add-ons,” as they are called, are considered the most likely cuts if Biden wants to reverse the previous administration’s elevation of nuclear weapons in U.S. strategy, due to resistance from military leaders to big changes as Russia and China build up their arsenals.

The Biden team is reportedly considering tweaking some of the language in the Trump-era stance to assert that the role of nuclear weapons is “fundamentally” to deter the use of nuclear weapons by others. That would be a departure from the 2018 Trump review, which stated explicitly that “deterring nuclear attack is not the sole purpose of nuclear weapons,” citing that they could be used to defend against a “non-nuclear attack.” Such a change would be more in line with the review completed in 2010 under the Obama administration, when Biden was vice president.

The White House declined to address specific questions about the review. A White House official said the administration “is committed to renewing American leadership in nonproliferation and addressing the existential threat posed by nuclear weapons.” The official added the review will “look at these issues” and “take account of the current security environment and will assess U.S. strategy, posture and policy.”

“I think we’ll probably see, certainly, a shift back towards the tone and tenor of the 2010 NPR,” said retired Air Force Lt. Gen. Frank Klotz, who co-authored a new study on the nuclear triad for the government-funded RAND Corp. But that also likely means sticking to the major overhaul of the nuclear triad that was underwritten in the Obama administration and is estimated to cost $634 billion over the next decade.

The Trump administration added to that modernization push byauthorizing at least three new weapon systems and upgraded warheads. Critics argue such less destructive weapons are more destabilizing because they are more likely to be used in a conflict than weapons that can obliterate entire cities.

Biden, however, has been under pressure from some Democrats in Congress to reconsider the development of the Ground Based Strategic Deterrent, which is set to replace the Minuteman III ICBMs that are located in underground silos across five Western states. A Pentagon-ordered unclassified study on the future of the ICBM force commissioned by the Pentagon in December isn't expected to recommend major changes to the missile replacement program, which was awarded to Northrop Grumman in 2020. The Biden nuclear review is also not expected to propose changes to the development of a new fleet of Columbia-class ballistic missile submarines under construction by General Dynamics, or the B-21 stealth bomber also being built by Northrop Grumman.

“Many of the same programs, many of the same policies will remain the same,” predicted Klotz, who ran the National Nuclear Security Administration at the Department of Energy, which builds the nuclear warheads, from 2014 to 2018.

One option under consideration is to remove the W76-2 nuclear warhead, a lower yield, or less explosive, bomb that the Trump administration called for in the 2018 review and was deployed on submarines the following year, officials said. But many see that as one of the more difficult decisions by Trump to reverse.

Another component of the arsenal that advocates consider more ripe for reversal is the Trump decision to keep the B83, the last megaton bomb that was developed in the 1970s but the Obama administration slated for retirement. Kristensen also pointed out that the B61-12 warhead, which had been designed to replace the B83, is now coming on line. “There is no need for it [the B83],” he said. “The military has been pretty clear about that. I’ve heard the bomber crews don’t even practice with it anymore.”

Also on the table is halting development of the Nuclear Sea-Launched Cruise Missile, a class of weapon that was retired after the 2010 Nuclear Posture Review but revived by Trump. More than $15 million in research funding was included in Biden’s first defense budget, but the administration has since shown tepid support for the program. It would be the first such weapon since the end of the Cold War, when earlier models were taken off warships and placed in storage.

Even for the relatively modest changes to the weapons portfolio being considered, there is likely to be strong resistance on the Hill and inside the Pentagon. Indeed, Biden’s review is shaping up to be a major win for hawks — and foreign allies who have reportedly lobbied against major policy changes.

China is rapidly expanding its nuclear arsenal and may have 1,000 nuclear warheads by the end of the decade as it aims to surpass U.S. global influence by the middle of the 21^st century, according to a major Pentagon report released on November 3. The estimate, based on the rapid modernization of China’s nuclear strike options and its construction of missile silos, marks a dramatic increase from the projection in last year’s China Military Power report, which estimated that China would double its stockpile of 200 warheads within a decade.

The report comes amid heightened tensions over the issue of Taiwan and was published hours after the most senior U.S. general, Chairman of the Joint Chiefs of Staff Mark Milley, issued a stark warning about China’s military progress, stating it amounts to “one of the largest shifts in global geostrategic power that the world has witnessed.”

A senior defense official briefing reporters on the report adopted a similar stance. “The nuclear expansion that the [People’s Republic of China] is undertaking is certainly very concerning to us,” the official said. “It’s one thing to observe what they’re doing, but they haven’t really explained why they’re doing it. They’re moving in a direction that substantially exceeds where they’ve been before in terms of numbers and capabilities,” the official said.

Though China still maintains a no first-use policy when it comes to nuclear weapons, the official said China has suggested “there are circumstances under which that wouldn’t apply.”

The investment in its nuclear force has allowed China to establish a nascent nuclear triad of air-launched ballistic missiles, as well as surface and sea-launched missiles, similar to the United States’ own triad. The U.S. currently has 3,750 nuclear warheads in its stockpile, according to the latest data from the State Department, dwarfing the size of China’s nuclear stockpile.

The Federation of American Scientists (FAS) also published a report the same week about the rapid building of three suspected silo fields in western China. The silo fields are still years away from becoming operational, wrote the authors of the FAS report, but they could eventually be capable of launching long-range nuclear missiles.

The Pentagon report also focuses on Beijing’s goals for future development and modernization of its armed forces. Crucially, if China meets its interim modernization goal for 2027, it could provide Beijing with “a range of different options” regarding Taiwan, from a blockade of the island to a potential amphibious invasion of either Taiwan itself or one of the smaller outlying islands. At the same time, China also aims to deter foreign intervention in what Beijing sees as a domestic political issue.

The outgoing Vice Chairman of the Joint Chiefs of Staff, General John Hyten, said that the pace at which China’s military is developing capabilities is “stunning,” while U.S. development suffers from “brutal” bureaucracy. Gen. Hyten told reporters at a Defense Writers Group roundtable that “the pace they’re moving and the trajectory they’re on will surpass Russia and the United States if we don’t do something to change it.”

The Pentagon has repeatedly referred to China as the “pacing challenge” for the U.S., but President Joe Biden stressed that competition does not make conflict inevitable.

Most people probably have not heard the term “nuclear sponge” before. We hadn’t until recently.

It refers to Nebraska, Wyoming, Colorado, Montana and North Dakota, where U.S. land-based intercontinental ballistic missiles (ICBMs) sit in underground silos, serving as a “sponge” for nuclear attacks by Russia, China or another adversary armed with nuclear weapons. The idea is the missiles in these states would be targeted, since the adversary knows exactly where they are, and would seek to destroy them before they could be launched in a nuclear war. As such, these missiles would draw at least some fire away from other natural targets, such as the national capital in Washington, D.C., or other large population centers.

Nobody asked the people in the Nebraska Panhandle, or in the other states, for their consent to be a nuclear sponge, or more accurately, a target.

Largely forgotten but not gone, 400 Minuteman III ICBMS have been in their silos since 1959, despite the Cold War having ended nearly 30 years ago. Now comes a Strangelovian plan to replace those missiles with new ones, in a program dubbed the Ground Based Strategic Deterrent (GNSD), or more properly, the Money Pit Missile.

The projected cost of our tax dollars for these new weapons of omnicide is $264 billion, according to the nonpartisan Congressional Budget Office. The overall cost of upgrading the entire U.S. nuclear weapons complex is projected by the CBO at $1.7 trillion over 30 years. Congress and three successive administrations, including the current one, seem unconcerned about the opportunity cost of this folly.

Surely, were there a national referendum on priorities, people would choose addressing climate chaos and pandemics, remedying racial and economic inequality, and creating green jobs by sustainably rebuilding the country’s crumbling infrastructure, over new nuclear weapons. Said weapons are supposedly only for deterrence, designed never to be used, to rust in peace.

If there were a nuclear war, all life on Earth would be at risk, as even a “limited” nuclear war, for instance between India and Pakistan, could cause nuclear winter, threatening the global food and water supply. As noted, the ICBMs are stationary, and their locations known by other nations’ militaries and by the farmers and ranchers whose land the silos abut. The other two legs of the U.S. nuclear triad, long-range bombers and nuclear submarines, are much harder to target. Bombers can be scrambled into the air, so they are not sitting duck targets for an attack, and submarines are stealthy, hiding deep in the world’s oceans. So the target and nuclear sponge element are unique to the ICBM force.

Perhaps if the people in these five states were fully aware of and consented to this arrangement, that would be copasetic. But no such consent was ever asked, nor granted, by the foreign policy elites, mostly on the east coast, who know and care little about the everyday concerns of folks in the Heartland and Mountain West.

Joe Biden has astutely talked about building a “foreign policy for the middle class,” but unfortunately it appears to be the same old foreign and military policy for the weapons contractors. His proposed $753-billion Pentagon budget is an increase over Trump’s bloated war budgets.

Northrop Grumman is the lead contractor on the Money Pit Missile Program, and not surprisingly, has spent millions in congressional lobbying and campaign contributions to make sure its bread is buttered and the GBSD gets built to fatten profits.

This is madness. Let’s wring out the nuclear sponge. Let’s take responsibility to lead in making Nebraska, the region, the country and world safer. Let’s stop the GBSD, and while we’re at it, why not ditch the entire ICBM leg of the nuclear triad? U.S. Sen. Ed Markey, D-Mass., and U.S. Rep. Ro Khanna, D-Calif., have introduced the ICBM (Investing in Cures Before Missiles) Act to cut funding for the Money Pit Missile, refurbish the existing Minuteman force as needed, and invest instead in a universal coronavirus vaccine.

Let’s lead on converting the nuclear missile bases to solar energy or wind farms, or whatever other more productive, less dangerous uses the communities now hosting missile silos need.

If we can eliminate one leg of the triad, then why not the others? Stopping the Money Pit missile could be an important step toward the global elimination of nuclear weapons, as 86 countries have agreed to by joining the Treaty on the Prohibition of Nuclear Weapons. Why not start here, and now, in Nebraska? This isn’t a liberal or conservative issue; it’s about human survival.

Paul Olson is professor emeritus at the University of Nebraska-Lincoln, the former president of Nebraskans for Peace, and a 75-year opponent of the arms race. Kevin Martin is president of Peace Action, the country’s largest peace and disarmament organization with 200,000 supporters nationwide, at peaceaction.org. His article was reprinted in PeaceMeal, Nov./December 2021.

The British branch of Pugwash Conferences on Science and World Affairs recently commissioned a survey of British public opinion in relation to NATO’s nuclear weapon policy. Asked whether they would wish NATO to engage in nuclear retaliation if Russia were to use nuclear weapons against one or more NATO members, 51 percent of respondents answered “yes.” The picture changed when the questions focused on the “first use” of nuclear weapons. Asked to consider the possibility of Russia invading one or more of the Baltic states without using nuclear weapons, 70 percent wished NATO to refrain from using nuclear weapons in any ensuing military operations, and 65 percent wished NATO to rely exclusively on non-nuclear weapons in such operations.The British government appears to be unaware of this public opposition or unready to be influenced by it. NATO’s 2010 strategic concept describes the alliance’s nuclear weapon policy as follows: “Deterrence, based on an appropriate mix of nuclear and conventional capabilities, remains a core element of our overall strategy. The circumstances in which any use of nuclear weapons might have to be contemplated are extremely remote.”

U.K. officials tend to believe that the threat of first use will cause potential aggressors to think twice before starting a non-nuclear conflict by sowing doubt about their ability to control escalation. The threat of first use is, they believe, the surest way of avoiding nuclear use.

This seems questionable. Is threatening first use of nuclear weapons a credible deterrent? As the use of nuclear weapons would turn front-line states into wastelands, potential aggressors can reason that public opinion in those states would be strongly opposed to first use; they can infer that this opposition would exercise a determining influence on the decision-making of democratic governments. A sufficiency of non-nuclear defensive capabilities would provide a more credible deterrent.

Retaining first use avoids having to engage in constructive diplomacy with “Putin’s Russia.” Back in the 1970s, NATO members held “mutual and balanced force reduction” talks with the Soviet Union. These talks were not easy but led eventually to the Treaty on Conventional Armed Forces in Europe. This established comprehensive limits on key categories of conventional military equipment. Realistically, 2020s diplomacy could aspire to producing a mutual balance of NATO and Russian non-nuclear forces in theaters where NATO fears Russian aggression (and Russia fears NATO aggression). It might even generate confidence in the absence of aggressive Russian intentions.

It can also be argued that first-use doctrine is built on speculation. It supposes that, once initiated, the use of nuclear weapons can be limited, and nuclear escalation avoided. There is no empirical evidence for this supposition. It would be more reasonable to suppose that the consequences of a resort to nuclear weapons would be unpredictable but potentially catastrophic.

To British Pugwash the case for NATO renouncing first use, getting to grips with uncertainty while engaging Russia diplomatically, and spending more on non-nuclear defenses, if necessary, seems compelling. On the evidence to date, the British government — apparently heedless of British public opinion — takes a different view. One can imagine a U.S. decision to advocate NATO renunciation of first use, prompting a British change of heart. In the absence of that, however, a ringing declaration on page 17 of the U.K.’s national report to the 10^th Non-Proliferation Treaty Review Conference will sound a little false: “The Nuclear Weapon States have a responsibility to reduce the risk of nuclear conflict.”

Peter Jenkins chairs British Pugwash. His article has been edited and was reprinted in PeaceMeal, Nov./December 2021.

In the early hours of October 30, 1961, a bomber took off from an airstrip in northern Russia and began its flight through cloudy skies over the frigid Arctic island of Novaya Zemlya. Slung below the plane’s belly was a nuclear bomb the size of a small school bus — the largest and most powerful bomb ever created.

At 11:32 a.m., the bombardier released the weapon. As the bomb fell, an enormous parachute unfurled to slow its descent, giving the pilot time to retreat to a safe distance. A minute or so later, the bomb detonated. A cameraman watching from the island recalled: “A fire-red ball of enormous size rose and grew. It grew larger and larger, and when it reached enormous size, it went up. Behind it, like a funnel, the whole earth seemed to be drawn in. The sight was fantastic, unreal, and the fireball looked like some other planet. It was an unearthly spectacle!”

The flash alone lasted more than a minute. The fireball expanded to nearly six miles in diameter — large enough to include the entire urban core of Washington or San Francisco, or all of midtown and downtown Manhattan. Over several minutes, it rose and mushroomed into a massive cloud. Within ten minutes, it had reached a height of 42 miles and a diameter of some 60 miles. One civilian witness remarked that it was “as if the Earth was killed.” Decades later, the weapon would be given the name it is most commonly known by today: Tsar Bomba, meaning “Emperor Bomb.”

Designed to have a maximum explosive yield of 100 megatons (100 million tons) of TNT equivalent, the 60,000-pound monster bomb was detonated at only half its power. Still, at 50 megatons, it was more than 3,300 times as powerful as the atomic bomb that killed at least 70,000 people in Hiroshima, and more than 40 times as powerful as the largest nuclear bomb in the U.S. arsenal today. Its single test represents about one tenth of the total yield of all nuclear weapons ever tested by all nations.

At the time of its detonation, the Tsar Bomba held the world’s attention, largely as an object of infamy, recklessness and terror. Within two years, though, the Soviet Union and the United States would sign and ratify the Limited Test Ban Treaty, prohibiting atmospheric nuclear weapons testing, and the 50-megaton bomb would fall into relative obscurity.

From the very beginning, the United States sought to minimize the importance of the 50-megaton test, and it became fashionable in both the United States and the former Soviet Union to dismiss it as a political stunt with little technical or strategic importance. But recently declassified files from the Kennedy administration now indicate that the Tsar Bomba was taken far more seriously as a weapon, and possibly as something to emulate, than ever was indicated publicly. And memoirs from former Soviet weapons workers, only recently available outside Russia, make clear that the gigantic bomb’s place in the history of Soviet thermonuclear weapons may be far more important than has been appreciated. Sixty years after the detonation, it’s now finally possible to piece together a deeper understanding of the creation of the Tsar Bomba and its broader impacts. The Tsar Bomba is a potent example of how nationalism, fear and high-technology can combine in a fashion that is ultimately dangerous, wasteful and pointless.

Even before the first atomic bomb was built, scientists in the United States had conceived of an even larger weapon, the “Super,” which would use the energy of a fission bomb to power nuclear fusion reactions in the heavy hydrogen isotopes deuterium and tritium — resulting in a much more powerful weapon than one fueled by fission alone. Such a weapon, they reasoned, could be scaled up to the megaton range, a thousand-fold increase over the kiloton weapons they were contemplating for World War II. Los Alamos researchers were doing calculations on fission-ignited fusion bombs with yields of 100 megatons by October 1944.

After the Soviet Union detonated its first atomic bomb in 1949, a tense debate over whether a crash H-bomb program was the proper response to the loss of the American nuclear weapons monopoly had leaked into the public, giving rise to speculation about the vast damage that could be caused by still-hypothetical megaton weapons. It was easy to apply scaling laws to see what the damage would be from such weapons. The 20-kiloton “Fat Man” bomb used against Nagasaki, for example, could devastate the downtown area of a large American city like San Francisco, Los Angeles or New York. A single 10-megaton bomb, though, could destroy entire metro areas, subjecting over a thousand square miles to a crushing blast wave and searing heat, easily producing casualties in the millions. The radioactivity produced would also be multiplied many hundreds of times, creating the possibility of vast contamination.

By the spring of 1951, Edward Teller and Stanislaw Ulam at Los Alamos had developed their design for a workable hydrogen bomb. The idea was superficially simple: Use the radiation of an exploding fission bomb (the “primary”) to compress a special capsule that contained both fusionable and fissionable materials (the “secondary”). A proof-of-concept device (“Sausage”) was tested in November 1952, achieving an explosive yield of 10 megatons. A more compact, weaponized version (“Shrimp”) was detonated in March 1954 in the Castle Bravo test, achieving a much higher yield than anticipated (15 megatons, or 1,000 times as powerful as the bomb dropped on Hiroshima) and surprising the scientists with more radioactive fallout than expected (which required the evacuation of occupied atolls downwind from the Marshall Islands test site).

Only a few months later, in July 1954, Teller made it clear he thought 15 megatons was child’s play. At a secret meeting of the General Advisory Committee of the Atomic Energy Commission, Teller broached, as he put it, “the possibility of much bigger bangs.” At his Livermore laboratory, he reported, they were working on two new weapon designs, dubbed Gnomon and Sundial. Gnomon would be 1,000 megatons and would be used like a “primary” to set off Sundial, which would be 10,000 megatons. Most of Teller’s testimony remains classified to this day, but other scientists at the meeting recorded, after Teller had left, that they were “shocked” by his proposal. “It would contaminate the Earth,” one suggested. Physicist I. I. Rabi, by then an experienced Teller skeptic, suggested it was probably just an “advertising stunt.” But he was wrong; Livermore would continue working on Gnomon for several years, at least, and had even planned to test a prototype for the device in Operation Redwing in 1956 (but the test never took place).

All of which is to say that the idea of making hydrogen bombs in the hundreds-of-megatons yield range was hardly unusual in the late 1950s. If anything, it was tame compared to the gigaton ambitions of one of the H-bomb’s inventors. It is hard to convey the damage of a gigaton bomb, because at such yields many traditional scaling laws do not work (the bomb blows a hole in the atmosphere, essentially). However, a study from 1963 suggested that, if detonated 28 miles (45 kilometers) above the surface of the Earth, a 10,000-megaton weapon could set fires over an area 500 miles (800 kilometers) in diameter. Which is to say, an area about the size of France.

The Soviet Union had been interested in the Super for about as long, having received espionage information about the early American thermonuclear effort. The Soviets appear to have made their own path to the hydrogen bomb, though, first pursuing a single-stage design (“Sloika,” a reference to a layered pastry), tested in 1953, that could “only” be detonated at about half a megaton (though sub-megaton, it would still be 25 times as explosive as the Nagasaki bomb, and capable of killing millions if used on a major metropolis). In the spring of 1954, Andrei Sakharov, Yakov Zeldovich and Yuri Trutnev, along with other Soviet physicists, developed their own version of a staged thermonuclear weapon, called RDS-37. The details of this are still somewhat cloudy, but it appears to have been a genuinely indigenous development, and it resulted in the test of a megaton-range weapon in 1955.

As in the United States, there were those in the Soviet Union who immediately began thinking of “bigger bangs.” In late 1955, Avraamiy P. Zavenyagin, a KGB general who was a minister of the nuclear program, proposed scaling up the program’s new H-bomb to a massive size. It would be nothing fundamentally innovative — the same RDS-37 design but with a lot more fuel, to produce a yield in the “many tens of megatons”; one document suggests 20-30 megatons. Work began on the weapon, dubbed RDS-202, in 1956, with design calculations made at Chelyabinsk-70 (the Soviet equivalent of the Livermore weapons laboratory) and procurement orders issued for the necessary materials.

The bomb’s physical dimensions would be gigantic: It would weigh 24–26 tons, with an eventual length of 26 feet (8 meters) and a diameter of over 6 feet (2 meters). Making the parts of such an oversized weapon proved almost beyond the capabilities of existing machine shops. The largest, front part of the casing alone required a “parquet” approach in which 1,520 smaller elements were welded together, and the casting of the internal spherical shapes required new manufacturing techniques.

But acting rapidly, the scientists and technicians had the bomb ready for testing in the fall of 1956 (Sakharov himself signed off on its warhead design). However, uncertainties about the possible effects of such a large weapon — and the scientists’ inability to reliably predict meteorological conditions that would affect both the distance of the blast effect and the fallout — led Soviet officials to postpone the test until additional studies could be done, which would end up taking years. Zavenyagin himself died on the last day of 1956, and, with him, so apparently did RDS-202. In March 1957, the Soviet government ordered that the project be put in long-term storage, and in 1958 decided to dismantle and recycle all the pieces of it. All that would remain in storage was the massive casing, which had been painstakingly engineered for its unusual ballistic properties.

Meanwhile, Soviet thermonuclear weapons design began to improve dramatically. Two young physicists at Arzamas-16 (the Soviet Los Alamos), Yuri Trutnev and Yuri Babaev, developed what they called a “new principle” for staged thermonuclear weapons. Project 49, as it was called, focused on optimizing the transfer of energy from the bomb’s primary to its secondary. This, coupled with better primaries and secondaries, allowed for a much more efficient warhead, capable of getting much bigger “bangs” out of a given weight and volume of material. Their new bomb design was finally tested in February 1958, with great success. Igor Kurchatov, the famed “father of the Soviet atomic bomb,” reported that year to the Congress of the Communist Party that now the Soviet Union had “even more powerful, more advanced, more reliable, more compact and cheaper atomic and hydrogen weapons.”

By the end of 1958, both the United States and the Soviet Union would agree to a voluntary Test Ban Moratorium. Their stockpiles would still grow, but innovation in the arms race — at least when it came to the warheads — was deliberately stifled by the lack of nuclear testing. This would continue until 1961, when Soviet Premier Nikita Khrushchev decided that Soviet nuclear testing should resume.

Khrushchev would claim, in his memoirs, that he was pressured by the scientists and the military to resume testing. But it is also clear from those around him that he felt the need to look tough to the world — and to the newly inaugurated President John F. Kennedy, whom Khrushchev judged weak. And the real instigator would be the crisis in Berlin, which was coming to a head in 1961, and would only be resolved with the construction of the city’s notorious wall toward the end of the year.

The Soviet Union was also, it should be noted, in a somewhat precarious strategic position. The Red Army was huge and vast, and its nuclear arsenal was rapidly growing, but its delivery vehicles did not allow it to threaten the United States homeland directly and credibly. The Soviets could threaten by proxy, to be sure. But the United States had a many-fold advantage in nuclear weapons, many of them ringed around the Soviet borders. The Soviet Union had tested its first ICBMs, but there were scarcely any deployed. These same tensions would, in a few years, lead Khrushchev to base missiles in Cuba, but prior to that they made Khrushchev desperate to appear tough.

On July 10, 1961, Khrushchev summoned the nuclear scientists from Arzamas-16 to the Kremlin, where he told them about his plan to resume testing that fall. Andrei Sakharov argued that further testing was unnecessary; Khrushchev was furious at his impertinence and snapped: “Sakharov, don’t try to tell us what to do or how to behave. We understand politics. I’d be a jellyfish and not Chairman of the Council of Ministers if I listened to people like Sakharov!”

Exactly how the idea of the 100-megaton device came up at this meeting is not entirely clear from the accounts, but it sounds like Khrushchev asked the scientists for proposals for future tests, and somebody (some authors say it was Trutnev) proposed that they build and detonate a 100-megaton bomb. Khrushchev seized upon the idea, reportedly announcing: “Let the 100-megaton bomb hang over the capitalists like a sword of Damocles!”

The 100-megaton bomb would be known internally as Project 602. The speed of its development is beyond impressive in retrospect: In a mere four months, the team would have to develop an entirely new weapon design for a totally untested yield range; build the device and fabricate the fissionable and fusionable material into the correct shapes; and devise a plan to safely test it. Sakharov would manage the whole project, with Trutnev and Babaev doing much of the design work, along with the young physicists Victor Adamski and Yuri Smirnov. Little has been released about the details of the design, but a few years ago two longtime participants in the Soviet and Russian nuclear programs revealed that it was what they called a “bifilar” design: There was a “main” thermonuclear unit in the center, with two “primaries” imploding it from either side (with a time difference between the two detonations of no more than 0.1 microseconds). This seems plausible given the documentary photographs of the bomb released by Russia after the Cold War, which definitely show one very compact “primary” bomb at the front end of the case, and hint at another at the back of the case. If this is true, it suggests that the 100-megaton bomb design was quite different from most thermonuclear weapons; there has never been a report of any American bombs, for example, that use multiple, simultaneous primaries. In the end, Sakharov made “some changes” in the design, to minimize the margin of error, which were implemented only days before the test.

Sakharov also made one major change to the test plan. Even though the test bomb was a 100-megaton design, it would not be a 100-megaton detonation. In most thermonuclear weapons designs, at least half the yield comes from a final stage in which non-fissile atoms of uranium 238 are induced to fission by the high-energy neutrons produced by deuterium-tritium fusion reactions. Replacing the uranium 238 with an inert substance, in this case lead, would make the weapon half as powerful (50 megatons), and it would release far less fallout in the form of fission products.

Sakharov was already queasy about the long-term deaths from nuclear fallout, and he wanted to minimize the excess radioactivity produced by the test. In 1958, he had calculated that for every megaton of even “clean” nuclear weapons, there would be some 6,600 premature deaths over the next 8,000 years across the globe, owing to carbon atoms in the atmosphere that would become radioactive under the bomb’s neutron flux.

A few thousand deaths — even the 660,000 that he thought would be the result of a 100-megaton test — would be a tiny amount compared with the billions who would live and die over those millennia, but they were still deaths Sakharov considered himself partially responsible for. Had he not reduced its yield by half, the 100-megaton bomb would have contributed about half as many fission products as were released by all nuclear tests prior to the test moratorium. As it was, even a bomb that was only 3 percent fission wasn’t exactly clean in an objective sense—as it still released almost two megatons of fission products. But in a relative sense (comparing fission yield to total yield), it was one of the cleanest nuclear weapons ever tested. Again, Sakharov would later state that he believed that if this worked, it could essentially end atmospheric nuclear testing: The Soviets would be able to “squeeze everything out of this [testing series] so that it would be the last one.”

On August 30, 1961, the Soviet Union issued a statement that it was abandoning the test moratorium. It, of course, blamed the United States, claiming the Americans were on the threshold of starting up nuclear testing underground, and emphasizing the defensive nature of the Soviet arsenal. The statement also referred to big bombs: “The Soviet Union has worked out designs for creating a series of superpowerful nuclear bombs of 20, 30, 50, and 100 million tons of TNT.” But it did not yet directly threaten to test weapons of such high yields.

The response from Kennedy and others was predictably negative (according to one advisor who was there, the president’s first reaction was “unprintable”). The Kennedy administration then agreed that the United States, too, would resume nuclear testing. The tests the Atomic Energy Commission (AEC) had ready to go were low-yield underground tests, which the White House thought might “invite such adverse comment” when compared to the larger Soviet tests “as to be unacceptable.” But AEC Chairman Glenn Seaborg managed to convince Kennedy that it was a bad idea to try to immediately test larger devices, and the White House would later use this fallout-free series of tests as a contrast to the multi-megaton Soviet test series.

Some American scientists chimed in that weapons of such size were “too big” to be practical — that such a weapon would be strategically pointless. The argument, which would come up again and again in discussion of these bombs, was based on the way in which blast damage scales with yield. A 100-megaton bomb releases 10 times more energy than a 10-megaton bomb, but it does not do 10 times more damage. This is because the blast effects of explosions scale as a cubic root, not linearly. So a 100-megaton explosion is only a little more than twice as damaging as a 10-megaton bomb. The weight of nuclear weapons, though, does roughly scale with their yield in a more linear fashion, so a 100-megaton bomb weighs roughly 10 times more than a 10-megaton bomb, which makes it much more difficult to deploy on a bomber or missile.

The point that would repeatedly be made is that it is easier to deploy multiple lower-yield weapons than to deploy more massive weapons (and it is worth noting the absurdity of considering even one-megaton weapons, capable of utterly destroying most cities and many of their suburbs, to be “lower-yield”).

As Soviet nuclear testing began at the start of September 1961, the protests continued. The Soviet test series was vigorous, with multiple tests per week, and yields ranging from less than a kiloton upward to a 12.5-megaton bomb by mid-October.

Finally, in his introductory speech to the Convocation of the 22^nd Congress of the Communist Party of the Soviet Union on October 17, Khrushchev made public his plan for the Tsar Bomba: “Since I have digressed from the prepared text, I might as well say that the testing of our new nuclear weapons is going on very successfully. We shall complete it very soon — probably by the end of October. We shall evidently round out the tests by exploding a hydrogen bomb equivalent to 50 million tons of TNT. (Applause.) We have said that we have a bomb as powerful as 100 million tons of TNT. And we have it, too. But we are not going to explode it, because, even if exploded in the remotest of places, we are likely to break our own windows. (Stormy applause.) We will therefore not do it yet. But by exploding the 50-million bomb, we shall test the triggering device of the 100-million one.”

The world response was immediate. The United States, of course, immediately denounced the plan as unnecessary: Even the development of 100-megaton bombs did not require a test of 50 megatons in strength, and the fact that the Soviets were doing it anyway “could only serve some unconfessed political purpose.” By October 27, the United Nations had passed a resolution that “solemnly appealed” to the Soviet Union to refrain from testing a 50-megaton bomb.

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China, in the midst of a rapid nuclear weapons buildup, will soon surpass Russia as the United States’ top nuclear threat, a senior U.S. military official said on August 27, warning that the two countries have no mechanisms to avert miscommunication.

U.S. Air Force Lieutenant General Thomas Bussiere, the deputy commander of the U.S. Strategic Command, which oversees the country’s nuclear arsenal, said China’s development of nuclear capabilities “can no longer be aligned” with its public claim that it wants to maintain a minimum nuclear deterrent. “There’s going to be a point, a crossover point, where the number of threats presented by China will exceed the number of threats that currently Russia presents,” Bussiere told an online forum.

He said the determination would not be based solely on the number of Beijing’s stockpiled nuclear warheads, but also on how they are operationally fielded. “There will be a crossover point, we believe, in the next few years,” Bussiere said.

Unlike with Russia, the United States did not have any treaties or dialogue mechanism with China on the issue to “alleviate any misperceptions or confusion,” he added.

Bussiere’s comments come as the United States is attempting to realign its foreign policy to put greater emphasis in the Indo- Pacific region to counter China’s growing economic and military might. Think-tank reports based on satellite imagery say China appears to be constructing hundreds of new silos for nuclear missiles, and Washington has accused Beijing of resisting nuclear arms talks.

China says its arsenal is dwarfed by those of the United States and Russia, and that it is ready for dialogue, but only if Washington reduces its nuclear stockpile to China’s level.

In a 2020 report to Congress, the Pentagon estimated China’s operational nuclear warhead stockpile to be in “the low 200s,” and said it was projected to at least double in size as Beijing expands and modernizes its forces.

According to a State Department fact sheet, the United States had 1,357 nuclear warheads deployed as of March 1.

China’s advances in missile technology to deliver those warheads are also a concern for the United States, and Bussiere said China last year tested more ballistic missile capabilities than the rest of the world combined.