There was a time not long ago when the nuclear arms race, although still a game of high stakes poker, was decidedly less complex. When the United States and the Soviet Union were the only players at the table, the game of deterrence was more predictable. But as others joined the game—Iran, North Korea, and Pakistan to name a few—the stakes were raised at the same time pressures to disarm increased.

In his recent paper, “Instability of Small Numbers Revisited: Prospects for Disarmament and Nonproliferation,” Charles L. Glaser, the Emmett Dedmon Professor in Public Policy, examines the case for nuclear disarmament in a new geopolitical field, investigating whether the barriers to disarmament are now lower and whether the incentives are greater than in the past. He concludes that, although disarmament has great intuitive appeal, maintaining a small nuclear force may be preferable to total disarmament.

Deterrence in a Post–Cold War Era

Security in today’s geopolitical world is difficult to guarantee. By the logic of Cold War politics, having nuclear weapons provided a form of security—the superpowers deterred each other with large forces that kept the arms race in check. When relations between the superpowers thawed, the nations began to consider how many weapons they still needed to feel safe. Some experts revisited the age-old question of disarmament. Lately, the threat of nuclear weapons falling into terrorists’ hands has created new urgency, with disarmament seen as a means of slowing nuclear proliferation.

But disarming and eliminating all weapons is a dicey game of trust and every country must worry about others who might cheat. Glaser argues that a state that agreed to disarm completely could be in trouble if suddenly faced with an adversary with even one nuclear weapon. Further, even if all states disarmed, what would happen if political relations suddenly soured and one side quickly rearmed? If a state was unprepared, it could easily find itself at a sizable disadvantage.

Many nations are still too insecure to feel comfortable with total disarmament. Since the Cold War ended, the international political landscape has changed. New players have entered the game and the dynamics between old players are continuing to evolve. Although U.S.-Russia relations have thawed they still are not warm enough, and potential conflict with China (most concretely over Taiwan) makes disarmament unrealistic. And, ironically, a unipolar world with the United States on top makes disarmament less likely: countries like Iran or North Korea now feel the need to arm themselves rather than rely on Russia as a counterbalance to the United States.

In response to these and related dilemmas, Glaser discusses several proposed solutions, including the role of strategic defense systems against nuclear weapons, an international nuclear force, and radically improved political relations. However, he points out that each has shortcomings. For example, a state that achieved an advantage in strategic defense capabilities would, in effect, have improved its ability to rearm. An adversary would then have to be able to rebuild more quickly than its opponent (the United States, for example) to hold its own in a rearmament race. While an international nuclear force could in theory be an effective solution, it would only be politically feasible if countries already completely trusted one another. Otherwise, fears about control of the international force would make the states unwilling to rely on the international authority to maintain their security. The third solution—radically improving political relations—confuses the problem with its solution. True, if relations improved to the point that the nuclear powers were confident that war would never occur, then they would be willing to give up their nuclear weapons. But in this case nuclear weapons do not pose a danger for these states, and they would still need to worry about non-nuclear states eventually acquiring nuclear weapons.

A Case for Moving to Small Numbers

There is little reason to believe that global political relations will ever meet the demanding standards required for disarmament, and therefore states will be unwilling to enter into such a risky agreement.

According to Glaser, moving to small nuclear arsenals is both more feasible and more desirable. Small arsenals provide a valuable hedge against the dangers of disarmament. If a state has some nuclear weapons that could survive an enemy attack it will be less threatened by the possibility of others’ hidden weapons and by disadvantages in and uncertainties about nuclear rearmament. Once nuclear forces are sufficiently small, an all-out war would be significantly less damaging than if fought with today’s large stockpiles. Further, political relations among leading nations are now good enough that arguments for very large forces are less compelling, making the potential risks of smaller nuclear forces more acceptable.

However, these smaller forces are not free from problems or risks. In contrast to small arsenals, large forces protect against a preemptive first strike. If the arsenal is large enough—even if a portion of the weapons are destroyed—the country will have enough remaining firepower for a massive response. But with smaller forces, a first strike could wipe out the entire stockpile, or at least significantly reduce its retaliatory capability. To prevent such crisis instability, countries would have to adopt strict planning criteria that guaranteed that their nuclear forces were highly survivable.

Although modest compared with disarmament, moving to small forces is still a highly ambitious goal. It would involve radical changes in nuclear states’ force structure, strategic doctrine, and operations. The nuclear powers would have to agree on the size of radically reduced forces and on how to monitor the arms agreement with high confidence. In addition, there would have to be global agreement on which states would be allowed to keep nuclear weapons.

Glaser argues that even faced with these important questions, the move to smaller nuclear arsenals would be more advantageous—and thus likely more feasible and ultimately more stable— than total disarmament. The large redundant forces that the United States built during the Cold War resulted from the combination of extremely cautious, worst-case analyses with a flawed understanding of the nuclear revolution. It can be argued that such risk-averse analysis was warranted given the chilly relations with the Soviet Union. However, relations today with Russia and China are much better, creating the opportunity for less risk-averse, although still prudent, nuclear planning—which points to a smaller nuclear force, rather than no force at all.