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.