Scott Sagan wrote a typically fine essay in the Spring 2000 issue of International Security on “The Commitment Trap.” His subject was the Bush administration’s use of “calculated ambiguity” to deter Saddam Hussein from using chemical or biological weapons in the run-up to the second Gulf war. After disavowing chemical weapons (1992) as well as biological weapons (1972), senior U.S. officials have sought to deter their use by others by issuing warnings of “absolutely overwhelming” and “devastating” responses. These code words imply the use of nuclear weapons.
Scott argued, persuasively in my view, that veiled threats to use nuclear weapons trapped U.S. officials. If CW or BW were actually used by an adversary — regardless of their scope and military effectiveness, whether from top-down dictates or breakdowns in command and control — Washington could feel impelled to carry out its threat, thereby inviting immeasurable but significant costs to its international stranding and to the Nuclear Nonproliferation Treaty. Alternatively, by refraining from carrying out its nuclear threat, Washington could also lose international standing, inviting new adversaries to call its bluff and old friends to question the protectiveness of the U.S. nuclear umbrella. To avoid these awful choices, Scott proposed that calculated ambiguity be replaced with a clear and credible U.S. commitment to respond to CW and BW use with prompt and devastating conventional retaliation.