They hinge their decision on the word "reasonable", which is refered to in the Constitution, in the 4th Amendment, in which it is written:

The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

So we get the impression from the court that as long as the TSA and the court (after the fact) think that a UNIVERSAL suspicion of every person trying to fly is a REASONABLE suspicion, a search is acceptable. The trouble is that the fourth Amendment specifically states that the right to be secure against unreasonable searches and seizures will not be violated. The second sentence explains what it requires the government to do if it believes there IS a "reasonable" search needing to be done. The determination of "reasonable" is associated with the issuance of the Warrant, PRIOR to the search, and stated publicly, with a aprticular person named, and a particular place or belonging to be searched.

The court doesn't care:

http://blogs.forbes.com/kashmirhill/2011/07/15/federal-court-rules-that-...

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