… it is worth remembering that the total number of people killed since 9/11 by al Qaeda or al Qaeda like operatives outside of Afghanistan and Iraq is not much higher than the number who drown in bathtubs in the United States in a single year, and that the lifetime chance of an American being killed by international terrorism is about one in 80,000 — about the same chance of being killed by a comet or a meteor. Even if there were a 9/11-scale attack every three months for the next five years, the likelihood that an individual American would number among the dead would be two hundredths of a percent (or one in 5,000).

Although it remains heretical to say so, the evidence so far suggests that fears of the omnipotent terrorist — reminiscent of those inspired by images of the 20-foot-tall Japanese after Pearl Harbor or the 20-foot-tall Communists at various points in the Cold War (particularly after Sputnik) — may have been overblown, the threat presented within the United States by al Qaeda greatly exaggerated. The massive and expensive homeland security apparatus erected since 9/11 may be persecuting some, spying on many, inconveniencing most, and taxing all to defend the United States against an enemy that scarcely exists.

John Mueller, “Is there still a terrorist threat?”, Foreign Affairs, September/October 2006