Many different groups in Washington are supposed to have studied all possible threats. I simply am unable to understand why so many brilliant people did not think of such a simple plot and devise adequate countermeasures. It is not hard to imagine that some people did think of it, but were ignored or muzzled.

P.S. Another puzzling thought. Why didn't the airlines, who are now threatened with bankruptcy, do more to make security measures more effective? More than any other group, they should have been aware of the inadequacy of airport security.