Contemplating Strategic Stability in a New Multipolar Nuclear World


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Robert Legvold
Meeting the Challenges of the New Nuclear Age

There are today approximately 13,800 nuclear weapons in the arsenals of nine nuclear weapons-possessing states. A 300-kiloton warhead—a common size of the weapons held by the United States, Russia, China, Great Britain, and France—carries the destructive power of 300,000 tons of TNT. If one of them was detonated over the Pentagon, which is a scenario that Lynn Eden has described, the superheated air would create a rapidly expanding fireball one mile wide and 200 million degrees of heat at its center.1 A half second later three quarters of a mile away at Pentagon City the streets would dissolve and metal surfaces would melt, and then a blast wave with 750 mile per hour winds would crush buildings and turn automobiles into fiery projectiles. Four seconds later the heat and blast would incinerate the Lincoln and Jefferson memorials, melt and crumple the aluminum exterior of planes at Reagan National Airport and set their interiors on fire. Three miles away the clothing of people outdoors would burst into flames and the exposed parts of their bodies would suffer third-degree burns. The detonation would create what is called, in something of an understatement, “a large area fire” with a radius between 3.5 and 4.5 miles producing hurricane force winds with temperatures above boiling (212 degrees Fahrenheit) and devastating an area 40 to 65 square miles—10 to 15 times wider than the 15-kiloton bomb used to destroy Hiroshima.

In a war leading to a nuclear attack on Washington, however, an adversary would not limit itself to using a single weapon but would likely target the city with multiple nuclear warheads, as the Soviet Union was prepared to do during the Cold War. The delayed and secondary effects in this case are potentially magnitudes greater. India and Pakistan have together between 270 and 290 nuclear warheads (many fewer than the 12,685 in the holdings of Russia and the United States). But were they to go to a large-scale nuclear war using most of them, as aspects of their current nuclear postures suggest they well might, the larger and more ramified consequences would dwarf the scenario described above. The radioactive fallout would drift as far as Australia; radiation contamination would poison the fresh waters of the rivers of the Himalayas reaching into China; and the dust, ash, and soot pumped high into the atmosphere would create a cloud that, if it reached the stratosphere, would not dissipate for several years, blocking sunlight and lowering temperatures that could eventually destroy crops and potentially cause the starvation of millions across Asia and beyond.2

Presumably, therefore, no nation’s leadership wants even one of these weapons to be used, and, following this logic, one might imagine that planning for their use would be frowned upon. In reality, however, one proposition does not follow from the other. Every government that has these weapons does plan for their use. At the most paradoxical level they do so on the assumption that planning for their use is the best way to ensure that they will not be used. At a more practical level, they—at least the most advanced and richly armed—do so, because they believe that planning for a limited and discriminating use of nuclear weapons may be essential to prevent an act of aggression short of an unlikely largescale surprise nuclear attack, and if it occurs to cut it short before nuclear escalation reaches the levels in the scenarios above.

The existence of nuclear weapons and the consequences were they to be used have for more than a half century prodded the two countries possessing most of these weapons to wrestle with the dilemma created: namely, how to ensure that your country’s nuclear posture, the weapons comprising it and the strategy by which they would be employed, will deter major aggression by the other side, while somehow minimizing the risk that in a political-military crisis an unintended or unwanted resort to nuclear weapons may happen. Resolving the dilemma came to be thought of as achieving strategic stability qua crisis stability. Often added to the concept was the notion of arms race stability, that is, efforts to avoid a pointless and potentially destabilizing nuclear arms race.

By the time the Soviet Union and the United States began negotiating limits on their nuclear forces in 1969, the gold standard basis for strategic stability was thought to be when each had and would be able to maintain a capacity, after suffering a large-scale nuclear attack, to deliver an overwhelmingly destructive retaliatory strike with its remaining nuclear weapons. No imaginable gain could, therefore, match its price. Not everyone on either side, including some insignificant policy-making roles, thought the concept made good sense, and remained wedded to the notion that escaping from the trap of mutual vulnerability should be the goal. Nor is it clear that the two governments embraced the concept at all times, or that, when either did, that it was more than a reconciliation with a reality as it was rather than the one they would have preferred.3

That was then. Today’s nuclear setting poses challenges and creates complexities that leave the relevance of the Cold War concept of strategic stability questioned even in the core U.S.-Russian nuclear relationship and in its new adjunct, the increasingly fraught U.S.-China nuclear relationship. And, if that is true in these cases, what notion in other two-way and often three-way nuclear relationships can serve to approximate strategic stability between and among them? Or is the future an unregulated matrix of states locked in competitive relationships, preoccupied with preventing the other side or sides from achieving a nuclear advantage, constrained only by economics and the technological barriers not yet breached, and indifferent to standards, mechanisms, or concepts blocking the pathways to inadvertent nuclear war in a proliferating number of contexts?

The American Academy of Arts and Sciences as part of its project on “Meeting the Challenges of the New Nuclear Age” asked a small group of senior experts (see Appendix I) to wrestle with these questions. What follows is not a report of their deliberations, let alone a consensus document, but one person’s exploration that addresses key themes raised during their discussions and exploits many of the insights generated by the participants.


  • 1Lynn Eden, Whole World on Fire: Organizations, Knowledge and Nuclear Weapons Devastation (Ithaca, N.Y.: Cornell University Press, 2004), 15–37.
  • 2The notion of “nuclear winter” and its potential sequel of “nuclear summer” are controversial and the science disputed. Since 1990, however, a series of studies have been done testing a variety of computational models, all of them hampered by a number of indeterminate variables. Most assume a regional nuclear war in which fifty to one hundred 15-kiloton weapons (Hiroshima size) are detonated. A 2006 study concluded that five million tons of soot would be released, cooling temperatures over large areas of North America and Eurasia by several degrees, including most of the world’s grain-growing regions, cooling that would last for years. A 2014 study projected ozone losses of between 20 and 40 percent over populated areas, increases in summer UV indices by between 30 and 80 percent over mid-latitudes, and a reduction of growing seasons by ten and forty days per year for five years.
  • 3The sole exception may have been the 1990 Soviet-United States Joint Statement on Future Negotiations on Nuclear and Space Arms and Further Enhancing Strategic Stability in which they pledged “to ensure strategic stability, transparency and predictability” by reducing their nuclear arms and working together “to improve the survivability” of their systems, to reduce “incentives for a nuclear first strike,” and to achieve “an appropriate relationship between strategic offenses and defenses.”