The official U.S. government policy is to maintain "calculated ambiguity" about whether the United States would retaliate with nuclear weapons in response to an adversary's use of chemical weapons (CW) or biological weapons (BW) against U.S. allies, U.S. armed forces overseas, or the U.S. homeland. Since the 1991 Gulf War, numerous civilian and military leaders have stated that the United States might use nuclear weapons in response to CW and BW threats or attacks, and some have even stated that the United States will use nuclear weapons in such circumstances. The central argument in my spring 2000 International Security article was that this policy has created a dangerous "commitment trap" problem.

The benefit of making such nuclear threats, whether stated ambiguously or clearly, is that they can increase an adversary's estimate of the probability that the U.S. president would order nuclear retaliation, which should therefore decrease the likelihood of chemical or biological weapons attacks. But there is a serious cost attached to this obvious benefit: If deterrence fails despite nuclear threats, the statements will also increase the likelihood that the United States will actually use nuclear weapons, because the president's personal and the U.S. government's institutional reputations for following through on threats would be perceived to be at stake.

I argued that current U.S. nuclear doctrine has therefore created a subtle dilemma that has not been recognized, much less debated, in both policy and academic circles: Is the improvement in the U.S. ability to deter CW and BW threats worth the increased likelihood of a U.S. nuclear response if deterrence fails?

A biological terrorist attack probably would first be detected by doctors or other health-care workers. The speed of a response would then depend on their rapid recognition and communication that certain illnesses appeared out of the ordinary. For this reason, preparing for biological terrorism has more in common with confronting the threat of emerging infectious diseases than with preparing for chemical or nuclear attacks. Defense against bioterrorism, like protection against emerging diseases, must therefore rely on improved national and international public-health surveillance. Too often, thinking about bioterrorism has mimicked thinking about chemical terrorism, a confusion that leads to an emphasis on the wrong approaches in preparing to meet the threat.

This paper focuses on the question of how much protection a building provides its inhabitants from a BW attack. The reason for considering this problem is simple: most people spend the majority of their daily lives inside buildings. In fact, the U.S. EPA estimates that average Americans spend approximately 87% of their time indoors.5 However, most previous technical assessments of BW incidents ignore the effects of buildings, computing casualties based only on integrated outdoor surface dosage. The protective effects of buildings have been considered for other toxic releases. Karlsson, for example, looks at the effects of indoor deposition upon toxic gas clouds,6 and Engelmann7 and others examine the sheltering effectiveness of buildings against respirable plutonium releases. In this paper we seek to extend these basic ideas to biological agents and to explore aspects of the problem that are unique to biological weapons.

The rest of this paper is organized as follows: A brief discussion of general aspects of biological weapons is first presented. Then, we introduce the method used to model the penetration of buildings by biological agents and discuss the factors that determine the sheltering effectiveness of a particular building. The paper concludes with a discussion of simple measures that individuals can enact to increase the sheltering effectiveness of a particular building.

The proliferation of chemical, biological, and nuclear weapons is now the single most serious security concern for governments around the world. Peter R. Lavoy, Scott D. Sagan, and James J. Wirtz compare how military threats, strategic cultures, and organizations shape the way leaders intend to employ these armaments. They reveal the many frightening ways that emerging military powers and terrorist groups are planning the unthinkable by preparing to use chemical, biological, or nuclear weapons in future conflicts.

Distinguished specialists consider several states and organizations that have this weaponry: Iraq, Iran, India, Pakistan, North Korea, and Israel, as well as the Aum Shinrikyo cult. The contributors expose plans for using unconventional weapons, highlighting the revolutionary effects these arsenals might have on international politics and regional disputes.

It is no exaggeration to say that arms control has undergone a revolution in the past decade. In the forty years since the bombings of Hiroshima and Nagasaki ended World War II and began the nuclear age, governments, organizations, and individuals have worked to reduce the threat of wars between great powers employing weapons of mass destruction-nuclear, chemical, and biological. Some progress was made during this period; the Limited Test Ban Treaty (LTBT) of 1963, the nuclear Non-Proliferation Treaty (NPT) of 1970, and the Anti-Ballistic Missile (ABM) Treaty and Biological Weapons Convention (BWC) of 1972 were the more notable achievements. But progress was always slow, frustrating, and tentative, with no assurance that the whole fabric might not be undone by an increase in superpower tension or by domestic forces in either the United States or USSR hostile to the very concept of arms control.

This article will consider whether the principles of the Geneva Protocol have become so widely accepted that they apply to the United States even though it is not a party. It will analyze the effect of existing reservations to the Protocol, discuss the United States use of tear gases and herbicides in Vietnam in light of its provisions, and recommend that the Protocol be approved by the Senate. This article will first describe the international agreements dealing with poison gas and germ warfare, and the reasons which prevented the United States from becoming a party to them.