Some threats to international security are so potentially damaging that preventing them in advance is preferable to remedying their effects. In such cases, states should judge preventive actions by a standard of legitimacy, not strict legality.
ABRAHAM D. SOFAER, George P. Shultz Senior Fellow in Foreign Policy and National Security Affairs at the Hoover Institution at Stanford University, served as Legal Adviser to the U.S. State Department from 1985 to 1990. This essay draws on a report, titled "The Best Defense? Legitimacy and Preventive Force," prepared for the Stanford University Task Force on Preventive Force, which will be published by Hoover Press on February 1, 2010.
After 9/11, U.S. President George W. Bush announced his determination to do whatever was necessary to prevent future terrorist attacks against the United States. Following the lead of several countries that had recently come to similar conclusions after their own bitter experiences -- including India, Israel, Japan, Russia, Spain, and the United Kingdom -- the United States tightened its immigration laws; increased the protection of its borders, ports, and infrastructure; criminalized providing "material support" for terrorist groups; and tore down the wall between the intelligence agencies and law enforcement agencies, which had crippled counterterrorist efforts for decades. Washington did not authorize preventive detention, as other countries had, but it used other measures to hold persons against whom criminal charges could not be brought -- thereby preventing terrorist attacks. The U.S. government also led or joined various international efforts aimed at warding off new dangers, such as the Proliferation Security Initiative, through which over 70 states cooperate to interdict the movement of nuclear materials across international borders.
But the Bush administration's call for preventive action went further: it endorsed using force against states that supported terrorism or failed to prevent it. This was a particularly controversial position, since using (or threatening to use) preventive force across international borders is generally considered to be a violation of international law: the International Court of Justice (ICJ) and most international legal authorities currently construe the United Nations Charter as prohibiting any use of force not sanctioned by the UN Security Council, with the exception of actions taken in self-defense against an actual or imminent state-sponsored "armed attack."
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