I love slate's Supreme Court Dispatches.

Justice Rehnquist cuts in to say that maybe there were only three instances of drug use because the drug-testing was such a great deterrent. Of course, that means that the program is fantastic either way: as a remedy had there been lots of evidence of drug use, a brilliant deterrent when there's none. Oh, bravo!

...

Of course, there is an argument to be made that parents who subject their good, achieving kids to unfounded, humiliating random urine tests are freaks. But that's not the court's position. The court thinks there's a drug problem in this country. True. And something needs to be done. Also true. And the court thinks it's not the fault of the government or the utter failure of its war on drugs. The failure, therefore, must be with those punks in the glee club. So, even if it's paternalistic and unfounded to deter (aka "control") good students with widespread terror and humiliation, they are, after all, merely "prisoners."