GAO recommends using that type of information to improve systematic threat assessments and refine federal program targeting. That will not be easy. By its nature, terrorism partakes of the irrational and will not always succumb to rational dissection by the tools of threat assessment and risk management. Any rigid ranking of terrorists' histories, capabilities, and intentions appears to equate likelihood with lethality, understating the threat posed by low probability, yet highly consequential, chemical and biological attacks. But the threat can just as easily be overstated.
Vulnerability alone is an inadequate measure, drawing scarce resources in a thousand directions.
Preparing for every worst case scenario is neither practical nor affordable, and carries the additional risk we terrorize ourselves by starving other fiscal priorities and surrendering civil liberties. As the threat of biological and chemical terrorism evolves, so should our response. Just as we learned to assess, and to a degree accept, the nuclear threat in the 1950s and 60s, our assessment of the risks posed by terrorism will need to adapt to the changing world environment of the next century. Federal programs, not known for flexibility or adaptability, will need to change as well. These are the issues we will confront today, and in future hearings as our oversight continues.