Morse is a bad example. If you want to hang a "Bong hits for Jesus" banner on your home, the government can't punish you (though your HOA might). That case hinges on the fact that it was in a school setting, and even though the Court says that children don't surrender their rights at the schoolhouse door, they pretty much do, to a degree. As a matter or prudence, public school children can't have carte blanche to behave however they want and then raise the First Amendment as a shield simply because it's "expressive conduct."
