The United States faces growing potential threats from state actors, their proxies, and independent extremists and terrorists. While various analysts may have tended to exaggerate the immediate threat or the current threat posted by given actors, the events of September 2001 show this scarcely means that the threat is not real or that the nation does not need to improve its defense and response capabilities. The United States must plan to defend against such threats not only to defend its own homeland, but also to protect its ability to deploy forces overseas and its allies.
The practical problem is to decide exactly how to be deal with highly uncertain emerging threats in a world where the United States has limited resources and many other priorities. The United States cannot bet the lives and well being of its citizens on today’s threats and probabilities. There are many potentially hostile foreign and domestic sources of such threats, and some key threats like biological weapons involve rapidly changing technologies that will pose a steadily growing threat to the U.S. homeland. U.S. involvement in the world, the strength of U.S. conventional and nuclear forces, and vulnerability at home are a dangerous combination, and unless the United States acts to improve deterrence and defense, the risk of major asymmetric and terrorist attacks involving CBRN weapons is likely to grow.
Finding the right mix of defense and response is extremely difficult, however, and it is far easier to call for dramatic action than to determine what actions will really succeed and be cost-effective and then execute them. It is clear from the preceding chapters that the federal government is making