In the late 1980s, a school district in Vernonia, Oregon, adopted a new program to crack down on teenage drug use. Maintaining that drug use was a serious problem among school athletes, the district made participation in athletics contingent upon an agreement to undergo urine tests.The program proceeded without complaint until 1991, when seventh grader James Acton refused to be tested as a condition of playing on the school football team. Acton’s parents took the district to court, arguing that the rule infringed on their son’s constitutional rights.

The Actons’ case eventually reached the Supreme Court, where, in 1995, a majority upheld the school district’s drug- testing program—a decision that outraged the American Civil Liberties Union (ACLU). According to the ACLU and others, testing students without any suspicion that they are...