What are the First Amendment rights of public school teachers?

The Ninth Circuit opines in Demers v. Austin.
http://verdict.justia.com/2013/09/13/precisely-how-much-academic-freedom-should-does-the-first-amendment-afford-to-professors-and-teachers-at-public-schools

The opinion:

http://law.justia.com/cases/federal/appellate-courts/ca9/11-35558/11-35558-2013-09-04.html