President Obama, in Russia this week, announced an agreement to reduce American and Russian nuclear warhead stockpiles to a range between 1,500 and 1,675 for each country. How did negotiators arrive at these numbers?
By counting up potential targets for a nuclear strike and then negotiating around that number. U.S. military planners dream up a variety of hypothetical conflicts with other nuclear powers and determine how many warheads would be required to destroy all the most important targets in each scenario. The estimate is periodically adjusted downward, as planners eliminate targets to accommodate the president's desire to reduce stockpiles and their own changing views about how much deterrence is truly required. The president then consults allies—like Japan and South Korea—under the U.S. protective nuclear umbrella before entering into negotiations with Russia. Recent treaties have specified acceptable ranges for warhead stockpiles, with the United States tending to stick around the upper limit and Russia the lower limit. (U.S. military planners are more conservative than their Russian counterparts, in part because more countries rely on American protection.)
The first stage in planning for a reduction of the nuclear arsenal takes the form of the Nuclear Posture Review, a periodic policy analysis conducted by the Department of Defense and several other agencies. This report informs the president of the current status and needs of the nuclear program. The president then issues vague guidelines to the secretary of defense about the purpose of the nuclear weapon program, such as whether a pre-emptive strike might ever be employed. Finally, the Pentagon issues a confidential set of strike options detailing how we might be willing to use our nukes.
Next, the strike options go over to the U.S. Strategic Command, where military planners apply them to hypothetical conflicts with six different adversaries: Russia, China, North Korea, Iran, Syria, and a nonstate actor resembling al-Qaida. Within each simulation, the planners count up potential targets in four categories: 1) military forces; 2) weapons of mass destruction infrastructure, like launch bases and storage facilities; 3) military and national leadership; and 4) war-supporting infrastructure, such as factories, rail lines, and power plants. The number of warheads necessary to destroy or cripple these targets is calculated, taking into account the possibility of mechanical failure. (Planners assume that 15 percent of the nuclear weapons will turn out to be duds.) The calculations also take stock of the need for redundancy, so there will be enough nukes for an attack even in the aftermath of a disabling first strike by an opponent.
While the plans do not envision simultaneous nuclear conflict with all six adversaries, the military does plan for the possibility that one nuclear power might take advantage of the conflict between two others, either through blackmail or an actual strike.
Under the 2002 SORT treaty, the last bilateral agreement, the United States and Russia were limited to between 1,700 and 2,200 operationally deployed strategic warheads apiece. This limitation refers only to warheads currently mounted on ICBMs, in submarines, or waiting to be loaded onto long-range bombers. Not included are strategic warhead reserves (many of which can be put into action within a few days) or the smaller, tactical nukes that can be delivered by cruise missiles or fighter jets. Currently, the United States possesses about 500 tactical nuclear weapons, compared with roughly 3,000 for the Russians.
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Explainer thanks Lisbeth Gronlund of the Union of Concerned Scientists and Hans Kristensen of the Federation of American Scientists.