The likelihood that terrorists may use chemical and biological materials may increase over the next decade. The basic principles of U.S. policy continue from the 1970's to today: make no concessions to terrorists, pressure state sponsors of terrorism, and apply the rule of law to terrorists as criminals. The Presidential Decision Directive (PDD) 39 contains three key elements of national strategy for combating terrorism: reduce vulnerabilities to terrorist attacks and prevent and deter terrorist acts before they occur; respond to terrorist acts that do occur and apprehend and punish terrorists; and manage the consequences of terrorist acts, including restoring capabilities to protect public health and safety and essential government services and providing emergency relief. A new PPD reflects recognition of the need for centralized interagency leadership in combating terrorism. The need for effective interagency coordination, both at the Federal level and among the Federal, State, and local levels, is paramount. Threat and risk assessments could help the government make decisions about how to target investments in combating terrorism and set priorities on the basis of risk, identify unnecessary program duplication, overlap, and gaps; and correctly size individual agencies’ level of effort. There are different sets of views and an apparent lack of consensus on the threat of terrorism -- particularly weapons of mass destruction (WMD) terrorism. 4 footnotes