Can There Really Be "Free Speech" in Public Schools?

I suggest, in this contribution to a just-published symposium on the Supreme Court's recent Morse decision (i.e., the "Bong Hits for Jesus" case), that the answer is "no":

The Supreme Court's decision in Morse v. Frederick leaves unresolved many interesting and difficult problems about the authority of public-school officials to regulate public-school students' speech. Perhaps the most intriguing question posed by the litigation, decision, and opinions in Morse is one that the various Justices who wrote in the case never squarely addressed: What is the basic educational mission of public schools, and what are the implications of this mission for officials' authority and students' free-speech rights? Given what we have come to think the Free Speech Clause means, and considering the values it is thought to enshrine and the dangers against which it is thought to protect, is it really possible for the freedom of speech to co-exist with the mission of the public schools? We all recall Justice Jackson's stirring rhetoric in the West Virginia flag-salute case: If there is any fixed star in our constitutional constellation, he proclaimed, it is that no official, high or petty, can prescribe what shall be orthodox in politics, nationalism, religion, or other matters of opinion[.] But, is this really true - could it be true? - in public schools?

Thoughts?