George Shultz, William Perry, Henry Kissinger, and Sam Nunn weighed in yesterday in the Wall Street Journal with a fervent plea to abandon mutual assured destruction (MAD), a doctrine that has underpinned U.S. strategic planning essentially since the late 1950s. MAD, the four eminence grises opine, has outlived its usefulness. In fact, our retention of a sizable nuclear arsenal to back up MAD, and the desire of other countries to acquire nuclear weapons to deter us, has undermined global security.

There is much to recommend in this op-ed, which is actually the third such essay by these unlikely allies (see also here; and Shultz and Perry here). All three op-eds stress the dangers posed by the proliferation of deadly weapons. All three touch on the immorality of targeting civilians in war. I agree that we should strive to reduce the size of the U.S. nuclear arsenal, and I am open to the suggestion that U.S. strategic planners reduce the role of nuclear weapons in our overall force posture. But if a shift of the magnitude suggested in yesterday's op-ed results in the United States playing a more active role in the world today, and necessitates an even larger and more intrusive conventional military presence around the world, then the costs and risks of that alternative strategy are likely to be too high.

Part of the reason why this is so is because the four do not discard the notion of deterrence, a concept as old as international relations itself. Rather, they write, "nations should move forward together with a series of conceptual and practical steps toward deterrence that do not rely primarily on nuclear weapons or nuclear threats to maintain international peace and security."

In effect, Shultz et al warn that a world becoming more dangerous, not less, requires the United States to redouble its efforts to calm international fears and resolve underlying conflicts. As they explain in the op-ed:

while the four of us believe that reliance on nuclear weapons for deterrence is becoming increasingly hazardous and decreasingly effective, some nations will hesitate to draw or act on the same conclusion unless regional confrontations and conflicts are addressed. We must therefore redouble our efforts to resolve these issues.

Achieving deterrence with assured security will require work by leaders and citizens on a range of issues, beginning with a clearer understanding of existing and emerging security threats.

I don't find such policy prescriptions particularly reassuring. Requiring the U.S. government -- and the U.S. military -- to become more involved in resolving the causes of international tension, and, ulimately, conflict, as we move away from MAD would compound the United States's fiscal and strategic overextension at precisely the time when a change of course -- one predicated on a less intrusive and less interventionist global posture -- is most warranted.

There is also evidence that the authors question the value of nuclear deterrence, in part because it has proved incapable of stopping brush fire wars and small-scale conventional conflicts. (Kissinger first made this argument in a book published in 1957). A reasonable counter is that it was precisely those types of small wars that spawned much larger wars in the past, before the advent of nuclear weapons. I will concede that the threat of massive retaliation hasn't stopped all forms of violent death, if the authors would concede that deaths from all forms of violence (both inter- and intra-state) are at historic lows, and that nuclear weapons have likely played some role in the emerging obsolescence of great power war, especially. (Three recent books -- here, here, and here -- stress that changing international norms have been the primary drivers of this phenomenon. I will concede that, to a point, but contend that nuclear weapons have played an important role in changing these norms).

Proposals to substantially reshape our nuclear posture and doctrine have merit. Measures to reduce the risk of accidental launch are eminently sensible. A serious move to reduce the U.S. nuclear arsenal should proceed. Ben Friedman and I have elsewhere called for a substantial reduction in the number of nuclear warheads in the U.S. arsenal, and a shift from a triad to a dyad for delivery. The various U.S. government agencies responsible for managing the nuclear arsenal have a spotty track record, and their budgets deserve closer scrutiny. Efforts to clamp down on fissile material are worthwhile, and should continue.

But strategic planners need to prepare for the world as it is, and as it is likely to be. Shultz et al do not call for the United States to unilaterally disarm; a world without nuclear weapons is exactly that. And, as this recent paper explains, recent moves to rationalize the U.S. nuclear posture, though perhaps sensible in their own right, are unlikely to be reciprocated by other nuclear weapon states such as China and India. As with earlier op-eds calling for the abolition of nuclear weapons, this latest offering hinges on an eventuality that is unlikely to materialize: an ironclad commitment from all other nuclear weapons states to match the United States's reductions warhead for warhead.