"It Takes Only a Handful of Nukes to Deter an Enemy."
Wrong. Advocates of further cuts argue that a secure second-strike capability -- the ability to absorb an attack and retain enough nuclear warheads to launch a devastating response -- is sufficient for nuclear deterrence. Although "secure" and "devastating" are imprecise terms, many analysts would say that a few dozen submarine-launched ballistic missiles, each with multiple warheads, is plenty because at-sea subs are difficult to target in a first strike and the firepower provided by, say, 200 nuclear weapons is impressive. By their logic, anything more is "overkill" that can be cut with little loss to U.S. security.
Although it is possible that no sane leader would intentionally start a nuclear war with a state that possesses even a small deterrent force, nuclear-armed states still have conflicting interests that can lead to crises. And it turns out that, contrary to widely held assumptions, the nuclear balance of power is critically important to how such disputes are resolved.
Recently, I methodically reviewed the relationship between the size of a country's nuclear arsenal and its security. In a statistical analysis of all nuclear-armed countries from 1945 to 2001, I found that the state with more warheads was only one-third as likely to be challenged militarily by other countries and more than 10 times more likely to prevail in a crisis -- that is, to achieve its basic political goals -- when it was challenged. Moreover, I found that the size of this advantage increased along with the margin of superiority. States with vastly more nukes (95 percent of the two countries' total warheads) were more than 17 times more likely to win. These findings held even after accounting for disparities in conventional military power, political stakes, geographical proximity, type of political system, population, territorial size, history of past disputes, and other factors that could have influenced the outcomes.
When the United States operated from a position of nuclear strength during the Cold War, it stopped the Soviet Union from building a nuclear submarine base in Cuba in 1970 and deterred Moscow from increasing support to its Arab allies in the 1967 and 1973 Arab-Israeli wars. By contrast, when the nuclear balance was less favorable to Washington, it was unable to achieve clear victories in crises against the Soviet Union -- for example, failing to roll back Moscow's 1979 invasion of Afghanistan.
In addition, qualitative evidence from the past 70 years shows that leaders pay close attention to the nuclear balance of power, that they believe superiority enhances their position, and that a nuclear advantage often translates into a geopolitical advantage. During the Cuban missile crisis, American nuclear superiority helped compel Moscow to withdraw its missiles from the island. As Gen. Maxwell Taylor, then chairman of the Joint Chiefs of Staff, wrote in a memo to Defense Secretary Robert McNamara, "We have the strategic advantage in our general war capabilities.… This is no time to run scared." Similarly, Secretary of State Dean Rusk argued, "One thing Mr. Khrushchev may have in mind is that he knows that we have a substantial nuclear superiority, but he also knows that we don't really live under fear of his nuclear weapons to the extent that he has to live under fear of ours."
We see similar patterns in South Asia. When asked years later why Pakistan ultimately withdrew its forces from Indian Kashmir during the 1999 Kargil crisis, former Indian Defense Minister George Fernandes cited his country's nuclear superiority. In the event of a nuclear exchange, he said, "We may have lost a part of our population … [but] Pakistan may have been completely wiped out."
This may sound crazy. To most people, "But you should see the other guy" would be scant consolation for losing perhaps millions of one's fellow citizens. But the truth is that nuclear war might well be more devastating for one country than for the other, even if both sides can inflict "unacceptable" damage. As Cold War nuclear strategist Herman Kahn wrote, "Few people differentiate between having 10 million dead, 50 million dead, or 100 million dead. It all seems too horrible. However, it does not take much imagination to see that there is a difference."
This is not to argue that leaders of countries with bigger arsenals believe they can fight and win nuclear wars. The logic is more subtle. Nuclear states coerce each other through brinkmanship. They heighten crises, raising the risk of nuclear war until one side backs down and the other gets its way. At each stage of the crisis, leaders make gut-wrenching calculations about whether to escalate, thereby risking a catastrophic nuclear war, or to submit, throwing an important geopolitical victory to their opponent. If the costs of nuclear war are higher for one state than another, then giving in will always look more attractive to leaders in the inferior position -- whatever payoff they might get from escalating would always be offset by a higher potential cost. So, on average, we should expect that leaders with fewer nukes at their disposal will be more likely to cave during a crisis. And this is exactly what the data show.
Competition between nuclear powers is like a game of chicken, and in a game of chicken, we should expect the smaller car to swerve first, even if a crash would be disastrous for both. The United States has always driven a Hummer, but it is trading it in for a Prius, even though games of chicken are likely for decades to come. Rather than cutting its forces, the United States should, as President John F. Kennedy promised, maintain a nuclear arsenal "second to none."
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