The Commitment Trap: Why the United States Should Not Use Nuclear Threats to Deter Biological and Chemical Weapons Attacks

The Commitment Trap Scott D. Sagan Why the United States Should Not Use Nuclear Threats to Deter Biological and Chemical Weapons Attacks Should the United States threaten to use nuclear weapons in retaliation for an adversary’s use of chemical or biological weapons? The U.S. government has a clear policy on this matter: it is deliberately unclear about its plans. In March 1996, Secretary of Defense William Perry explained: “For obvious reasons, we choose not to specify in detail what responses we would make to a chemical attack. However, as we stated during the Gulf War, if any country were foolish enough to use chemical weapons against the United States, the response will be ‘absolutely overwhelming’ and ‘devastating.’”1 The purpose of this U.S. policy—which has become known as the “calculated ambiguity” doctrine—was underscored by Secretary of Defense William Cohen in November 1998: “We think the ambiguity involved in the issue of nuclear weapons contributes to our own security, keeping any potential adversary who might use either chemical or biological [weapons] unsure of what our response would be.”2 The doctrine’s proponents, both inside and outside the U.S. government, claim that such a threat to respond asymmetrically—retaliating with nuclear weapons in response to a chemical or biological weapons attack—is an unfortunate necessity. They argue that, because the United States has foresworn the option of retaliating in kind, nuclear weapons threats are the only strong deterrent preventing so-called rogue nations from using their newly acquired chemical or biological arsenals.3 The calculated ambiguity doctrine, however, International Security, Vol. 24, No. 4 (Spring 2000), pp. 85–115© 2000 by the President and Fellows of Harvard College and the Massachusetts Institute of Technology. 85 Scott D. Sagan is Associate Professor of Political Science and Co-Director of the Center for International Security and Cooperation at Stanford University. For their helpful critiques of drafts of this article, I thank George Bunn, Sumit Ganguly, Timothy V. McCarthy, George Perkovich, William J. Perry, Daryl G. Press, Jonathan B. Tucker, Dean Wilkening , and four anonymous International Security reviewers. 1. Convention on Chemical Weapons (Treaty Doc. 103–21), Hearing before the Committee on Foreign Relations, U.S. Senate, 104th Cong., 2d sess., prepared statement by William J. Perry, March 28, 1996, p. 123. 2. Quoted in Dana Priest and Walter Pincus, “U.S. Rejects ‘No First Use’ Atomic Policy: NATO Needs Strategic Option, Germany Told,” Washington Post, November 24, 1998, p. A24. 3. The United States is constrained by its obligations under the Biological Weapons Convention (BWC) and the Chemical Weapons Convention (CWC) neither to possess nor to use chemical and biological weapons. The United States unilaterally destroyed its biological weapons stocks in the is deeply controversial because the U.S. government, and the governments of other nuclear weapons states, have made commitments, most recently before the 1995 Nuclear Non-Proliferation Treaty (NPT) extension conference, that they will neither use nor threaten to use nuclear weapons against any nonnuclear member state of the NPT.4 Efforts to back away from such promises, critics argue, undercut these global commitments, legitimize nuclear weapons threats, and encourage nonnuclear states to develop the bomb to deter their dangerous neighbors. The U.S. calculated ambiguity doctrine raises two crucial questions. Is the threat of U.S. nuclear retaliation credible and effective against states that possess chemical weapons (CW) and biological weapons (BW)? Are such U.S. nuclear threats harmful to global efforts to inhibit the proliferation of nuclear weapons? This article addresses these issues and argues that the current debate has virtually ignored what is arguably the most important question about U.S. nuclear weapons doctrine: will the U.S. government’s calculated ambiguity policy increase or decrease the likelihood that nuclear weapons will be used in combat? I conclude that the current policy is misguided because it increases the likelihood that the United States will use nuclear weapons, in an inappropriate manner, in future military conºicts. The calculated ambiguity doctrine should therefore be replaced with a stronger commitment to respond to the use of chemical or biological weapons with prompt and devastating conventional retaliation. I develop this argument in ªve parts. First...