New Jersey v. T.L.O (1985)
In New Jersey v. T.L.O. the US Supreme Court ruled for the first time when and how students could be searched in schools. T.L.O. were the initials of a 14-year-old girl at Piscataway High School who, with another student, was suspected of smoking in the bathroom, which was a violation of a school rule.  A teacher took both students to the office of the Assistant Vice Principal Theodore Choplick.  One admitted smoking but T.L.O. denied it.  Mr. Choplick insisted on searching her purse, and found a package of cigarette rolling papers, some marijuana, a pipe, some empty plastic bags, money, and a list of names.  He then notified her mother and the police.  After T.L.O confessed to selling marijuana at the school, delinquency charges were brought against her.  She argued in juvenile court that the evidence, and her confession, should be thrown out under the "exclusionary rule" because there was no warrant or "probable cause" to search her and her Fourth Amendment rights had been violated.  The juvenile court decided there was a "reasonable" basis to conduct the search, and sentenced her to a year's probation.

The US Supreme Court then reviewed the constitutionality of the search.  It asked: "How, then, should we strike the balance between the schoolchild's legitimate expectations of privacy and the school's equally legitimate need to maintain an environment in which learning can take place?"  Ruling that the requirement of a warrant before a search could take place was "unsuited to the school   environment," the Court decided that "a search of a student by a teacher or other school official will be justified when there are reasonable grounds for suspecting that the search will turn up evidence that the student has violated or is violating either the law or the rules of the school." Students could not simply be searched at random at the whim of the school.  A search "will be permissible in its scope when the measures adopted are reasonably related to the objectives of the search and not excessively intrusive in light of the age and sex of the student and the nature of the infraction."

Dissenting justices in the 6-3 ruling were troubled by the vague "reasonableness" standard laid down by the majority.  They said its "only definite content is that it is not the same test as the 'probable cause' standard found in the text of the Fourth Amendment.  In adopting this unclear, unprecedented, and unnecessary departure from generally applicable Fourth Amendment standards, the Court carves out a broad exception to standards that this Court has developed over years of considering Fourth Amendment problems." 

In the words of Justice Stevens, "The schoolroom is the first opportunity most citizens have to experience the power of government...the values they learn there, they take with them in life.  One of our most cherished ideals is the one contained in the Fourth Amendment: that the government may not intrude on the personal privacy of its citizens without a warrant or compelling circumstance.  The Court's decision today is a curious moral for the Nation's youth... ."