You might be interested in this news item.
I just posted this on another thread but it looks like it might be of some use in this one too:
The First Amendment protects the right of citizens to express themselves in a variety of ways. Public school students, as young citizens, may engage in many modes of expression — from the words they speak to the ideas they write and even the clothes they wear.
Students can engage in political speech, which is considered the type of speech at the core of the First Amendment. The Founding Fathers considered such speech essential to the development of a constitutional democracy. The U.S. Supreme Court spelled out those rights in a case concerning public school students who spoke out on a major political issue of their time — the Vietnam War.
cont'd..........
http://www.firstamendmentcenter.org/Speech/studentexpression/topic.aspx?topic=speakingout