What reason did the Supreme Court give for ruling as it did in Vernonia School District v. Acton?

The case of Vernonia School District v. Acton had to do with the drug testing of student-athletes in the public schools.  Acton argued that requiring all student-athletes to be tested violated the 4th Amendment prohibition against illegal searches and seizures.  The Supreme Court ruled against Acton by a 6-3 vote, saying that mandatory drug testing was constitutional.  Their basic reasoning was that the students do not have a legitimate expectation of privacy and that the degree to which their privacy is violated is outweighed by the school’s interest in preventing drug use.

The Fourth Amendment only protects against searches and seizures where someone has a reasonable expectation of privacy.  If, for example, you have a four-foot fence around your yard next to a sidewalk, you have no reasonable expectation of privacy in that yard because anyone can see over the fence and into the yard.  The Supreme Court ruled that the student-athletes had very little expectation of privacy.  Students in general already have a lower level of expectation of privacy because they can, for example, be required to have vaccinations, to have their hearing tested, and to have their vision tested.  Athletes have even less expectation of privacy because, among other things, they have to have physical exams to play and they have to change in front of everyone in locker rooms.  Because of all of this, student-athletes have very little reason to expect privacy.

Even if someone has a reason to expect privacy, that expectation is overridden if the government has a very strong need to do so (the technical term is interest in doing so).  In this situation, the Court ruled that the school had a very strong interest in keeping students from doing drugs.  Since the students had little right to expect privacy and since the school had a strong interest in drug-testing, the Court ruled that the drug tests were constitutional.