John Mueller has a provocative essay at (the excellent) Cato Unbound. I don’t have time discuss it right now. But it’s worth taking a look, if only to invite debate. Here’s the opener:

With the fifth anniversary of 9/11, a central question repeatedly asked is whether that country has become safer from international terrorism or not. I have never quite understood precisely what this question means, but let me explore six possibilities. 1. Is the likelihood that an individual American will be killed by international terrorists higher or lower than before 9/11? This is a tricky concept to deal with because the number of Americans killed within the United States by international terrorists in the five years since 9/11 is the same as the number killed in the five years before: zero. Although polls continue to show Americans notably concerned that they or members of their families might die at the hands of terrorists, astronomer Alan Harris has calculated that, at present rates and including the disaster of 9/11 in the consideration, the chances any individual resident of the globe will be killed by an international terrorist over the course of an 80-year lifetime is about 1 in 80,000, about the same likelihood of being killed over the same interval from the impact on the Earth of an especially ill-directed asteroid or comet. At present, Americans are vastly more likely to die from bee stings, lightning, or accident-causing deer than by terrorism within the country. That seems pretty safe.