The Limits of Damage Limitation

Charles L. Glaser and Steve Fetter Reply:

We thank Matthew Kroenig and Brendan Green and Austin Long for their letters in response to our article “Should the United States Reject MAD?”¹ The letters raise a variety of conceptual, strategic, and technical issues. Length limitations allow us to deal only with those criticisms we believe are most important.²

Kroenig argues that we err by searching for an “arbitrary threshold for meaningful damage limitation,” implies that we envision damage limitation as a binary variable instead of a continuous one, and holds that any damage-limitation capability would be valuable because “[a]ny U.S. president would want to protect as much of the country as possible.” Kroenig misunderstands our discussion and exaggerates the marginal value of reducing damage when the United States would suffer such high levels of retaliatory destruction that it might never again be a functioning state. We offered three ways of conceptualizing damage limitation: (1) a threshold above which additional damage results in costs that are small compared to costs at the threshold; (2) a threshold above which the United States would be unable to recover in anything resembling its current form; and (3) a threshold above which the United States should be unwilling to risk even a small increase in the probability of nuclear war to reduce the damage of an allout war. Although none of these variants fully captures the issues involved in judging the value of reducing the size of a nuclear attack, each offers valuable insights and the latter two are connected to key policy judgments.

Kroenig argues that any reduction in the size of a nuclear attack is worth pursuing because otherwise “saving millions of American lives is unimportant or politically irrelevant.” Yet, what if those surviving millions were fated to lives of misery, famine, and disease, struggling for mere survival in a “smoking radiating ruin?”³ Saving those lives would have value, but far less than saving lives in today’s United States. If saving these lives involved no economic costs, the United States might pursue a damage-limitation capability as insurance against an even worse outcome. But if the cost of being minimally successful were hundreds of billions of dollars per decade, the insurance might not be worth the price. Moreover, because the probability of all-out nuclear war with China is very low, the expected value—that is, the probability multiplied by the value of the damage limitation—is orders of magnitude smaller. Other uses of U.S. resources to save and improve the quality of American lives would have to be compared to the expected value of damage limitation. Any such calculation would be complicated, but we expect that, above some level of nuclear destruction, additional damage limitation would not warrant the investment. Damage limitation can nevertheless be worth the investment at low levels of nuclear destruction, and we have written elsewhere about the potential value of such a capability against small nuclear arsenals.⁴

An even more telling counterargument is that a damage-limitation capability would not only be economically costly, but would also increase the probability of nuclear war. Pursuit of the highly competitive policies required to preserve a U.S. damage-limitation capability would strain the U.S.-China relationship, increasing the probability of both conventional and nuclear war. It would also create strategic incentives for both the United States and China to escalate to the use of nuclear weapons and possibly increase the probability of their accidental and unauthorized use. Given the modest benefits of damage limitation at such high levels of damage, the increased risk of nuclear war would more than offset the benefits, resulting in a negative expected value for U.S. pursuit of a damage limitation capability.

Kroenig also claims that we fail to understand “nuclear deterrence in the wake of the nuclear revolution,” arguing that we “underestimate how damage limitation enhances deterrence and extended deterrence.” There is a critical gap in Kroenig’s argument. The logic of the nuclear revolution applies to two countries that possess assured-destruction capabilities; in other...