In Tinker v. Des Moines, the Supreme Court ruled that the wearing of a black armband in protest of the Vietnam War was not a substantial disruption of the school environment and was therefore protected speech.
It is the first major case to determine the speech rights of students.
In Hazelwood v. Kuhlmeier, the Supreme Court placed a limit on the speech rights of students when it ruled that it was permissible for a school to censor the actions of a school newspaper.
This is important as it provides a limit on the speech rights of students.
At issue in both cases are how the speech is disruptive to the school environment and many cases since then have hinged on the importance of the speech (protest in Tinker v. spreading gossip in Hazelwood) and the manner in which the speech is undertaken.