As far as the courts are concerned, "public education is inherently a situation where the government is the speaker, and ... its employees are the mouthpieces of the government," said Vikram Amar, a professor at UC's Hastings College of the Law in San Francisco. Whatever academic freedom exists for college teachers is "much, much less" in public schools, he said.Glad he distinguished a bit between college-level and lower-level teachers, since Amar teaches at a public school where I never heard a professor hesitate much before espousing personal political views. Because clearly, for Hastings anyway, there was never a problem with this kind of expression in the classroom - academic environment be damned.*
*I do think the situations are distinguishable - if a teacher is asked a question direcly, a teacher should be able to answer, if able and willing. Contrast that with a situation where a professor decides to wax poetic about whatever political view moves him or her that day.