I think I read this Bruce Schneier piece somewhere else before Christmas, but it obviously resonates even more now.
Stories are what we fear. It's not just hypothetical stories -- terrorists flying planes into buildings, terrorists with explosives strapped to their legs or with bombs in their shoes, and terrorists with guns and bombs waging a co-ordinated attack against a city are even scarier movie-plot threats because they actually happened.
"Security theater" refers to security measures that make people feel more secure without doing anything to actually improve their security. An example: the photo ID checks that have sprung up in office buildings. No one has ever explained why verifying that someone has a photo ID provides any actual security, but it looks like security to have a uniformed guard-for-hire looking at ID cards.
This whole idea of "theater" makes me uneasy; it reminds me of how many ideological screens there are between me and what I think I am experiencing. I see through the demeaning hassles at aviation-screening checkpoints, mainly because they inconvenience me and don't make me feel any more secure about anything. But what of the ideologies that are convenient to me, that do smooth my passage through my life while hiding from me the "realities"? Should I even worry about that?
The misconceived "security theater" at airports is so disturbing because it fails so spectacularly to bring the threats to our peace of mind under control. The ideology is too apparent -- no one believes that X-raying shoes will prevent would-be terrorists from coming up with a new way to evade security checks. Everyone knows the stories the TSA reacts to are yesterday's news, and the future is unwritten. The lack of imagination in the TSA responses makes us all too aware of how unlikely it is they will anticipate any coming threats.