Hours-long waits in the security line. Ridiculous prohibitions on what you can carry onboard. Last week's foiling of a major terrorist plot and the subsequent airport security graphically illustrates the difference between effective security and security theater.
None of the airplane security measures implemented because of 9/11 -- no-fly lists, secondary screening, prohibitions against pocket knives and corkscrews -- had anything to do with last week's arrests. And they wouldn't have prevented the planned attacks, had the terrorists not been arrested. A national ID card wouldn't have made a difference, either.
Instead, the arrests are a victory for old-fashioned intelligence and investigation. Details are still secret, but police in at least two countries were watching the terrorists for a long time. They followed leads, figured out who was talking to whom, and slowly pieced together both the network and the plot.
The new airplane security measures focus on that plot, because authorities believe they have not captured everyone involved. It's reasonable to assume that a few lone plotters, knowing their compatriots are in jail and fearing their own arrest, would try to finish the job on their own. The authorities are not being public with the details -- much of the "explosive liquid" story doesn't hang together -- but the excessive security measures seem prudent.
But only temporarily. Banning box cutters since 9/11, or taking off our shoes since Richard Reid, has not made us any safer. And a long-term prohibition against liquid carry-ons won't make us safer, either. It's not just that there are ways around the rules, it's that focusing on tactics is a losing proposition.
It's easy to defend against what the terrorists planned last time, but it's shortsighted. If we spend billions fielding liquid-analysis machines in airports and the terrorists use solid explosives, we've wasted our money. If they target shopping malls, we've wasted our money. Focusing on tactics simply forces the terrorists to make a minor modification in their plans. There are too many targets -- stadiums, schools, theaters, churches, the long line of densely packed people before airport security -- and too many ways to kill people.
More at Schneier's blog.