n July 10, 2001, the New York Times published an opinion article titled “The Declining Terrorist Threat.” It was written by Larry C. Johnson, a former CIA analyst and State Department counterterrorism official, who argued that Americans spent too much time worrying about terrorist attacks that would likely never come. “Judging from news reports and the portrayal of villains in our popular entertainment,” Johnson wrote, “Americans are bedeviled by fantasies about terrorism.” And then: They seem to believe that terrorism is the greatest threat to the United States and that it is becoming more widespread and lethal. They are likely...