【正确答案】 Most experts believe that an ever-increasing number of countries and terrorist groups will gain the technical capability to acquire and use chemical and biological weapons. But use of these weapons by hostile states or terrorist groups is not inevitable. Even when locked in bloody conventional wars, nations that have considered using these weapons have generally been deterred by the risk that their opponents would retaliate in kind or escalate the conflict elsewhere. Terrorist groups with the technical capacity to acquire and use a chemical or biological weapon have typically lacked an interest in doing so, while groups interested in such weapons have generally lacked the necessary technical skills.
Assessing future threats, however, involves more than simple extrapolation from past trends. In the case of chemical and biological weapons, it appears that the likelihood of use by both hostile states and terrorist groups is growing, and it is clear that even one such attack against an unprotected population could be devastating.