Charles Mann tests the TSA's security theater and concludes that "To walk through an airport with Bruce Schneier ["one of America’s top security experts"] is to see how much change a trillion dollars can wreak. So much inconvenience for so little benefit at such a staggering cost."
Schneier's money quote: “The only useful airport security measures since 9/11, were locking and reinforcing the cockpit doors, so terrorists can’t break in, positive baggage matching”—ensuring that people can’t put luggage on planes, and then not board them —“and teaching the passengers to fight back. The rest is security theater.”
James Fallows has more. Much more.