Bruce Schneier speaks sense for the nth time.

We confiscate liquids, screen shoes, and ban box cutters on airplanes. We tell people they can't use an airplane restroom in the last 90 minutes of an international flight. But it's not the target and tactics of the last attack that are important, but the next attack. These measures are only effective if we happen to guess what the next terrorists are planning.

If we spend billions defending our rail systems, and the terrorists bomb a shopping mall instead, we've wasted our money. If we concentrate airport security on screening shoes and confiscating liquids, and the terrorists hide explosives in their brassieres and use solids, we've wasted our money...

Unfortunately for politicians, the security measures that work are largely invisible. Such measures include enhancing the intelligence-gathering abilities of the secret services, hiring cultural experts and Arabic translators, building bridges with Islamic communities both nationally and internationally, funding police capabilities -- both investigative arms to prevent terrorist attacks, and emergency communications systems for after attacks occur -- and arresting terrorist plotters without media fanfare.