Definitions of WMD

The most widely used definition of "weapons of mass destruction" in official U.S. documents is "nuclear, chemical, and biological weapons."

The U.S. president has used this definition in communications with Congress.

• "Letter to Congressional Leaders Reporting on Proliferation of Weapons of Mass Destruction," November 9, 2000, Weekly Compilation of Presidential Documents, pp. 2842-2851.
• "Statement on Domestic Preparedness Against Weapons of Mass Destruction," May 8, 2001, Weekly Compilation of Presidential Documents, pp. 718-719.

The Central Intelligence Agency (CIA) has used this definition in reporting on proliferation to Congress.

• Unclassified Report to Congress on the Acquisition of Technology Related to Weapons of Mass Destruction, 1 January Through 30 June 2000.

The U.S. Department of Defense has used this definition in a series of major reports to Congress on proliferation threats and on measures for countering proliferation.

• U.S. Department of Defense, Proliferation Threat and Response 2001, "Message of the Secretary of Defense," refers to weapons of mass destruction as those with "...capabilities to inflict mass casualties and destruction: nuclear, biological and chemical (NBC) weapons or the means to deliver them." (page 4 on the screen)

The U.S. Government Accounting Office (GAO), the investigative arm of Congress, has used this definition, as well.

• U.S. General Accounting Office, Weapons of Mass Destruction: State Department Oversight of Science Centers Programs (May 10, 2001), opening letter to Senators Mitch McConnell and Patrick Leahy, describing the document as reviewing U.S. programs to help former Soviet scientists who once developed "nuclear, chemical and biological weapons systems."

Some U.S. laws likewise use this traditional definition of WMD.

• The Weapons of Mass Destruction Control Act of 1992, Title XV of the Defense Authorization Act of 1993, P.L. 102-484 (enacted October 23, 1992), relates "to the proliferation of nuclear, biological, and chemical weapons (weapons of mass destruction) and their related technology . . .."

This definition of WMD is also used internationally.

• Guidelines for Sensitive Missile-Relevant Transfers of the Missile Technology Control Regime (MTCR) refers to WMD as "nuclear, chemical, and biological weapons."

However, some more recent U.S. laws, official statements, and documents define WMD as including additional types of weapons, such as radiological weapons or conventional weapons causing mass casualties. Often these laws and documents are focused on responding to possible WMD incidents in the United States.

• The definition in the U.S. Code, Title 50, "War and National Defense," includes radiological weapons. It defines WMD as "any weapon or device that is intended, or has the capability, to cause death or serious bodily injury to a significant number of people through the release, dissemination, or impact of - (A) toxic or poisonous chemicals or their precursors; (B) a disease organism; or (C) radiation or radioactivity."

Further Reading:

	Arms Control Today, Wolfgang Panofsky, "Dismantling the Concept of 'Weapons of Mass Destruction"
	MIT, Allison Macfarlane, "All Weapons of Mass Destruction Are Not Equal"
	CRS, Sharon Squassoni, "Nuclear, Biological, and Chemical Weapons and Missiles: Status and Trends"
	WMDC, George Perkovich, "Deconflating 'WMD'"
	Weapons of Mass Destruction Commission, Weapons of Terror: Freeing the World of Nuclear, Biological and Chemical Arms