If it is so easy to pull off an attack and if terrorists are so demonically competent, why have they not done it? Why have they not been sniping at people in shopping centers, collapsing tunnels, poisoning the food supply, cutting electrical lines, derailing trains, blowing up oil pipelines, causing massive traffic jams, or exploiting the countless other vulnerabilities that, according to security experts, could so easily be exploited? …. If al Qaeda operatives are as determined and inventive as assumed, they should be here by now. If they are not yet here, they must not be trying very hard or must be far less dedicated, diabolical, and competent than the common image would suggest.