Did America overreact to 9/11? This is a question that is much in the air today. Consider, as one example, the essay that recently appeared in the Los Angeles Times written by David A. Bell, a professor of history at Johns Hopkins. The title of the piece is "Putting 9/11 into perspective," and its by-line reads: "The attacks were a horrible act of mass murder, but history says we're overreacting." But does "history" in fact tell us any such thing? Simply put, Bell's argument goes as follows: There have been wars in the past, global wars, in which millions have...