One impediment to undertaking a reasonable response to 9/11 is that, psychologically speaking, it feels as if the response should somehow be proportionate to the devastating emotional impact of the attacks. And when you contemplate the possibility of something even more horrible, like a nuclear attack on a city, then it seems like the preventive measures taken should, again, be incredibly dramatic. And yet the nitty-gritty of serious non-proliferation policy is deadly dull.
This is indeed a serious problem. One purpose of terrorism as a whole (not just WMD terror) is to compel an overreaction. The burden of this reaction will fall on those the terrorists or insurgents hope to recruit. But while it is one thing for a policymaker to understand this on an intellectual basis, it's another to actively market proportional policy solutions to the an understandably aggrieved public with a need to see some form of security theater.