Columbia Public Law & Legal Theory Working Papers

Document Type



In Future Challenges in National Security and Law, edited by Peter Berkowitz (Stanford, CA: Hoover Institution Press, 2010).


During the 2008 presidential campaign, then-candidate Barack Obama stated: “Sometimes, the preventive use of force may be necessary, but rarely. The experience of Iraq underscores that often, perceived threats are not as real [as] they may seem, and our intelligence may be imperfect. But, when our intelligence is good and defensible we should not rule out the use of force.” This chapter examines ways of assessing legally whether that intelligence is sufficiently good and defensible. It argues that an objective reasonable necessity approach to WMD capability assessments can serve long-term peace and security objectives and, more specifically, how the law governing use of force might evolve to guide capability assessments. A reasonable necessity approach, combined with an objective standard of assessing WMD capability and operating as a narrow legal alternative to formal U.N. Security Council authorization, can best balance and allocate competing risks in an environment of significant capability uncertainty. Moreover, the substantive evidentiary issues forced to the surface through objective reasonableness analysis are critical to managing some of the dangers of operating outside explicit U.N. Security Council authority, and are critical to the effective operation of the legal processes that the strict UN Charter constructionists advocate.

Date of Authorship for this Version

Spring 5-24-2010