In his recent article in Foreign Affairs, “Why Iran Should Get the Bomb: Nuclear Balancing Would Mean Stability,” Kenneth N. Waltz is swimming upstream against the consensus position regarding the instability stemming from nuclear proliferation. In this case, the consensus position is right, and Waltz is wrong.

The international nuclear nonproliferation regime is based on the logical proposition that with each additional nuclear-armed state, not to mention non-state actors, the deterrence dynamic becomes marginally more complex and diminishes the prospects for maintaining both crisis and arms race stability. The Heritage Foundation has conducted two table-top exercises to explore the prospects for maintaining nuclear stability in proliferated settings. The results of these exercises bolster the consensus view that nuclear proliferation can lead to unstable outcomes. Managing deterrence in a proliferated setting is a daunting task.

The first exercise examined crisis stability issues. There were nuclear weapons exchanges in two of the four iterations of the exercise. While there were a variety of contributing factors to the unstable outcomes, two stand out. The first was that is that it can be very difficult to perform the juggling act of deterring two or more simultaneous nuclear threats that result from proliferation.  For example, deterring a threat from North Korea toward South Korea may undermine the effort to deter a threat from China toward Taiwan. The second was that the coalition dynamic became too complex to manage. For example, attempts by a more senior partner in a nuclear coalition to restrain his junior partner can be interpreted as an invitation for aggression by an opposing coalition against the junior partner.

The second exercise examined arms race stability issues. Here, it becomes clear that as the appetite for obtaining nuclear weapons grows, so does the appetite for obtaining more of them. In this case, the real-world experience along the bilateral lines of the Cold War showed that the U.S. and Soviet policies of nuclear deterrence led to rapid growth in nuclear arsenals on both sides. “Balancing” may have led to some level of crisis stability, but it certainly did not lead to arms race stability.

There is one implicit point in Waltz’s article, however, that deserves favorable consideration. This point is that the U.S. and its allies must demonstrate that they have the ability to respond effectively to the circumstance of proliferation and maintain their security.

Some members of the nonproliferation consensus believe that the only answer to the problem is to move immediately to nuclear disarmament. On this point, this faction of the nonproliferation consensus is wrong. Such fatalism is likely to prove to be, well, fatal. Demonstrating the determination to respond effectively to proliferation can and should be seen as means for discouraging it.

It is logical for would-be proliferators to draw the wrong conclusion from the argument that the only answer to proliferation is disarmament, which is that the West has no effective means for responding to nuclear weapons. There should be little doubt that the task of managing deterrence and stability in a proliferation will prove daunting, but it is one the U.S. and its allies must do their best to address.