Norm Geras joins the debate:
[U]nlike car accidents and other such fatalities, deaths due to terrorism are being actively procured by the country's enemies; and for a government to respond in a laid-back way to an effort to kill hundreds, or – as it might also be – thousands of its citizens would invite charges of fecklessness and irresponsibility. It is its duty to take threats of this sort very seriously. If a government doesn't try to protect the country's citizens from enemy attack that is a major delinquency. So, while over-reaction is certainly not a good idea, vigilance, and vigilance that is plain and visible, is very much to the point.
A few days ago Matt Frost tried to understand the actions of DHS secretaries:
I pulled the same data that Nate did, and get the same aggregate totals for his ten-year period. But dividing those numbers out to the level of the individual passenger makes no sense to the managers responsible for maintaining the system. Nobody cares what your odds of being a victim are. What matters to the security principals is the risk of one catastrophic failure in the entire system during their tenure.
Say you are the Secretary of Homeland Security, and you plan to serve for four years before getting the hell out and working on Wall Street. There will be almost 3 million enplanements during your tenure. Aircraft for which you are nominally responsible will fly almost 30 billion miles. If we must do the Nickelodeon Numerology game, it would take light about 43 hours to go that far in space! Using Nate’s estimate of one terrorist per 11.5 billion miles flown, you can expect about 2 1/2 incidents on your watch. Look busy!
The Dish 