Nobody knows more about airport security that Bruce Schneier, and his work on subverting the TSA formed one of the central arguments of my doctoral thesis.  Bruce has a new essay up that is worth checking out – if for no other reason than the importance of keeping this issue alive:

The Constitution provides us, both Americans and visitors to America, with strong protections against invasive police searches. Two exceptions come into play at airport security checkpoints. The first is "implied consent," which means  that you cannot refuse to be searched; your consent is implied when you purchased your ticket. And the second is "plain view," which means that if the TSA officer happens to see something unrelated to airport security while screening you, he is allowed to act on that.

Both of these principles are well established and make sense, but it's their combination that turns airport security checkpoints into police-state-like checkpoints.

The TSA should limit its searches to bombs and weapons and leave general policing to the police - where we know courts and the Constitution still apply.