The threat posed by weapons of mass destruction (WMD) has become one of the most important, if not the most important, issue on security and foreign policy agendas at the beginning of the twentyfirst century. Iraq's alleged pursuit and possession of WMD dominated the international security agenda from President Bush's speech to the United Nations (UN) General Assembly in September 2002, (1) through UN Security Council Resolution 1441 providing Iraq one last opportunity to comply with previous Security Council Resolutions, (2) and culminating in the U.S. and British invasion of Iraq in March 2003. Through the Bush Doctrine, (3) the world's leading political and military power has made WMD a centerpiece of a new strategic doctrine designed to guide the assessment of national security threats and the application of U.S. power. (4) As illustrated by the Bush Doctrine, the WMD threat includes possession of these weapons by not only states but also terrorist groups, leading to fears about the rise of catastrophic terrorism (5)--fears exacerbated by the historic terrorist attacks against the United States on September 11, 2001. The U.S.-led military action against Iraq represented the application of the Bush Doctrine against the WMD-centered "axis of evil." Significant security concerns about WMD have also developed and grown more alarming with regard to North Korea's nuclear weapons capability (6) and Iran's possible nuclear weapons program. (7)
These recent developments involving the threat posed by WMD reflect a trend in the security area stretching back more than a decade. The end of the Cold War sparked a host of concerns regarding WMD in the hands of rogue states and terrorists, forcing policy makers, scholars, and pundits to assess the seriousness of the WMD threat and construct responses designed to address it. (8) The Bush Doctrine and the war against Iraq are the latest, and the most dramatic, policy moves by the United States to address the perceived WMD peril.
The rise in the prominence of WMD on security and foreign policy agendas in the 1990s and early 2000s raises questions about the role of international law in this area. International law has a long relationship with efforts to control WMD that began as early as the late nineteenth century with the development of treaty prohibitions on the use of poisonous gas in warfare. (9) As the International Court of Justice's Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons illustrates, (10) three bodies of international law regulate WMD: arms control treaties, international law on the use of force, and international humanitarian law. Historically, the most prominent and direct use of international law in connection with WMD was through arms control treaties--international agreements designed to prohibit or limit the development, possession, and use of nuclear, chemical, and biological weapons by states. (11) As Table 1 shows, only arms control treaties specifically address the development and use of WMD. Through such treaties, states and international organizations crafted a body of international law dealing directly with the control of WMD.
This body of international law reflects the "arms control approach" to WMD--formal agreements among states to regulate the use and development of WMD. According to Kellman, the arms control approach comprises "measures to cope with a dangerous threat to international security: vertical and horizontal weapons proliferation among national militaries, with concomitant acceleration of both the likelihood that war among nations will erupt and that, if and when war does break out, the consequences will be catastrophic." (12) The arms control approach had origins in international humanitarian law's prohibition of the use of weapons that cause superfluous injury or unnecessary suffering, (13) but the approach created an area of international law distinct from the laws of war because it developed a body of rules that applied prior to the outbreak of armed conflict. …