For the past seven years, the United States has been negotiating a verification protocol to the Biological Weapons Convention of 1972, hoping to put teeth into the convention's ban on biological weapons production. The Bush administration recently rejected the latest draft of the protocol, viewing it as irredeemably flawed. This is a good time to ask what a new American strategy should be for security against biological threats. It is difficult to predict the likelihood or scale of biological attack. The right policy will provide benefits whether or not an attack occurs.