The United States faces a dilemma with respect to its nuclear arsenal. On one hand, it, like the other Nuclear Weapon State (NWS) parties to the Nuclear Nonproliferation Treaty (NPT), made a commitment toward a “good-faith” effort to disarm at the earliest possible date. Because of this, there is pressure to reduce arsenals and discontinue warhead development. Non-Nuclear Weapon States (NNWS) are becoming increasingly unhappy with the lack of progress on this front (as witnessed by the 2005 NPT Review Conference debate), and the cracks in the foundation of the regime have become apparent.
On the other hand, there is a prevailing notion that the strategic stability of deterrence is lost at low numbers of warheads. Deterrence is premised upon the notion that a nuclear attack will invite a retaliatory strike of massive consequence. At small numbers of weapons, one side may begin to believe that they can destroy their enemy’s capacity to retaliate through a coordinated first strike, a limited missile defense, or a combination of both. This condition is destabilizing because, if one side is motivated to attack (either because they want war or because they think the other side wants war) they will be much more likely to act if they believe the opposition arsenal can be negated.
There are ways to make even a small arsenal highly survivable, but these often have their own destabilizing effects. Putting the warheads on submarines makes them both mobile and hidden in a vast space. Of course, it also makes the opposition anxious that the enemy might pop up off their coastline and fire missiles in a manner that would give them very little response time. Limited time to respond is the enemy of sound judgement.
Given this opposing conditions, the US would like to reduce its arsenal, but only to a point at which there remains a stable deterrence. However, there are a number of issues straight from the headlines that complicate the situation yet further. Many people in the Departments of Energy and Defense would like to produce a new type of warhead dubbed the Reliable Replacement Warhead. A central argument for such a project is that increasing the reliability of the component warheads would allow the US to go to smaller numbers because it would not require as great a buffer for margin of error. However, a great deal of controversy arises because building a new warhead represents a step back from the good-faith effort to disarm, and, if it requires testing to validate, it will further create tension among the nuclear have-not states that are already seeing progressively less reason to participate in the NPT. Of course, some say that the RRW is not really a new warhead because it does not offer new capabilities, and that it might be able to enter the arsenal without the conduct of a physical test. The Congress as of late has not been willing to continue funding on this project; thus intimating where it falls in the debate.
Missile defense creates a barrier to arsenal reduction. Presuming a missile shield is developed which is believed to be functionally effective, missile defenses reduce the ability to conduct a retaliatory strike, and states need to maintain larger arsenals to ensure that they can overwhelm these defenses. If the US has a missile shield, other countries become less likely to be willing to reduce their arsenals or may even see fit to increase the size of their arsenal. This, of course, makes it politically difficult for the US to unilaterally draw down its forces. The Bush Administration has been having this argument with Russia, which is concerned about the missile shield under negotiation in Europe that would involve sites in Poland and the Czech Republic. Putin has announced a plan to target Central Europe and has discussed other ramifications of such a site. The US has stated that the system would only involve 10 interceptors, and is, therefore, designed only to deal with a rogue proliferator such as Iran (against which it is directed) and has no capacity to negate the Russian arsenal.
Ultimately, the question of concern is how low can a nation go while still maintaining a functional deterrent capability? This depends upon a number of the factors addressed above including: how reliable the arsenals are, whether there are defensive systems in place, and whether the arsenals are hidden and/or mobile. However, the question also requires assumptions be made about the stability of the current state of affairs. For example, if one anticipates that the relevance of nuclear arsenals will be maintained at the current level, one will likely draw different conclusions about minimal deterrence then if one believes actions will be taken to reduce the relevance of nuclear weapons as suggested by the two Op-Eds by Kissinger, Perry, Shultz, and Nunn. Actions to reduce the relevance of arsenals may allow states to squeeze down to lower numbers sooner.
There are also the assumptions about what national decision makers feel is acceptable loss. I suspect that these losses would be much lower than Cold War planners estimated. Consider the economic and political ramifications of an event such as 9-11, which might be considered minor compared to the loss to be incurred as a result of even a crude nuclear device detonated at ground level in a densely populated area. Of course, because we don’t at the moment have a good way to model “acceptable loss”, we would expect over-the-top estimations to be presented in order to be on the safe side. In other words, we would expect to have to be able to unleash a great deal more retaliation to deter an opponent than it would probably actually take to do so.
