Columbia Public Law & Legal Theory Working Papers

Document Type



Forthcoming in Michigan Journal of International Law, vol. 31 (2009).


The Iraq war rekindled debate—a debate now further inflamed in discussions of Iran and North Korea—about the legal use of force to disarm an adversary state believed to pose a threat of catastrophic attack, including with weapons of mass destruction (WMD). Colliding with this debate is the stark fact that intelligence about hostile states’ WMD capabilities is and will remain limited and uncertain. This Article examines the following question: How should international legal rules on the use of force handle this intelligence gap? In answering that question, this Article advances two arguments. First, it argues that amid such intelligence uncertainty, a “reasonable necessity” approach to international self-defense doctrine, based on objective standards, is superior to the two main competing schools of thought: the “traditional view,” which holds strictly that only the U.N. Security Council may authorize legal force against WMD proliferators absent an imminent and specific threat of attack, and the “unilateralist” school, which holds that states retain a broader right of preemptive self-defense. Second, it argues that a reasonable necessity approach—and its reliance on objective standards—helps focus analysis on key evidentiary issues that have so far eluded serious study in scholarship on the legal use of force and that are relevant to ongoing debates about alleged WMD proliferation by Iran, North Korea and other states.

Date of Authorship for this Version

Fall 11-22-2009