When the Government acts as a kindergarten through twelfth grade educator, they are allowed to restrict speech in certain instances. The Supreme Court ruled in Tinker v. Des Moines School Dist. (1969) that restriction is permissible only when speech "materially and substantially interferes with the requirements of appropriate discipline in the operation of the school".[60] Later court decisions added more situations where restrictions were possible, including student speech about drugs,[61] "vulgar and offensive" language,[62] and school-operated newspapers.[63] The primary basis for the educator-distinction is based on the concept of in loco parentis, the principle that the school functions as parents over the students, thus allowing broader discretion in limiting student speech and expression.[64]