One case holds that searches and seizures conducted by public school officials constitute State action under the fourth amendment of the U.S. Constitution; further, a warrant and probable cause are not required for such searches; the standard for such a search is "reasonableness under all the circumstances." Another Supreme Court ruling holds that government employers do not need a warrant or probable cause to conduct work-related searches of their employees' offices, desks, or file cabinets; in another case the Court ruled that a probation department does not need a warrant or probable cause to search a probationer's home. A fourth case holds that the collection and testing of an employee's urine constitutes a search and seizure and that employees in safety-sensitive positions can be compelled to submit to urine testing in the absence of a "reasonable suspicion" that drugs have been used by the subject. The final case reviewed upholds suspicionless urine testing of government employees who are promoted to drug-interdiction positions or positions requiring them to be armed.