In January 2002 President George W. Bush signed a bill appropriating more than a billion dollars to help states prepare for a biological attack. However, some people argue that biological warfare—much like nuclear warfare—is potentially so devastating that U.S. government efforts should be focused as much on preventing it as preparing for it. Barbara Hatch Rosenberg, a biology professor and peace activist, asserts that preparing for biological warfare “by strengthening public-health response measures is . . . very important, but it is not enough. Prevention must be our goal.”

A central component of prevention efforts has been the use of international treaties. In 1925 many nations signed the Geneva Protocol, which banned the military use of biological (and chemical) weapons; the treaty stated that such weapons were “justly condemned by the general opinion of the civilized world.&rdquo...