For almost 40 years, the U.S. Supreme Court has held that searches conducted without a warrant are unreasonable under the fourth amendment of the U.S. Constitution. The Court has also stated that school children have legitimate expectations of privacy while at school, including privacy expectations regarding personal items they bring onto school grounds. This privacy expectation, however, must be balanced against legitimate societal concerns regarding safety and a secure learning environment. The Court has stated that there is a need for teachers and school administrators to have the freedom to maintain order in the schools. Accordingly, the U.S. Supreme Court concluded that strict adherence to the probable cause requirement of the fourth amendment for searches conducted by school officials is unnecessary. For searches by school officials that target specific students, the standard for warrantless searches is a reasonable suspicion rather than a reasonable belief that the student has been involved in a crime or rule violation. Based on this standard of reasonable suspicion, the search must be justified at its inception and be limited in scope to the violation at issue in the suspicion. This means that the lawfulness of evidence obtained from a warrantless search on school grounds depends on the evidence being related to the initial reasonable suspicion that a particular school rule or law had been violated by the student. Courts have also allowed suspicionless general searches of student property and lockers that involve drug testing or the search for weapons, holding that these threats are sufficiently serious for student safety as to warrant random suspicionless general searches.