Earlier quoted context omitted.
What doesn't make sense about this decision is its clear lack of constitutional basis. How does an opinion (via statute) on illegal drug use conflict with a constitutional amendment?
I'm trying to work out how the First Amendment was trumped for students based on historical opinion! Can someone clarify?
I have always been confused by this, as well. IANAL, but the reasoning seems to be based in the need of educators to reduce disruption and offensiveness, at the cost of protected speech. This wikipedia article [1] does a good job laying out the history of opinions on the subject.
[1]: http://en.wikipedia.org/wiki/School_speech_(First_Amendment)