Tinker v. Des Moines (1969): School officials cannot censor content except when necessary to avoid material and sunstantial interference with school work or discipline... or the rights of others. Students cannot be punished merely for expressing their personal views on school premises. Only speech that materially and substantially interferes with the requirements of appropriate discipline can be found unacceptable and therefore prohibited.

Bethel v. Fraser (1986): The First Amendment rights of students in the public schools are not coextensive with the rights of adults in other settings.

Cantwell v. Connecticut (1940): The Court ruled that the public on the street corner must in the interest of fostering enlightened opinion tolerate speech that tempts the listener to throw the speaker off the street.