Speakers more profound than I - including Adam Shostack and Bruce Schneier - have weighed in on the Western approach to terrorism countermeasures, a recent example of which is the searching of bags and packages carried by people entering New York City subway stations.
Countermeasures like this spring up far too quickly. They must be subjected to a more critical process, so, as one of the New Yorkers commented, the terrorists don't simply hit us where we're weak (e.g., shopping malls... before the decade's out, I'd bet). Otherwise, how are we to know whether the trade-offs we've accepted are good ones?