Under the Supreme Court's decision in Tinker v. Des Moines Independent Community School Dist., students in public schools are allowed to wear political statements to school (the case concerned black armbands protesting the Vietnam war, back when we had student protests against wars), so long as they are not “disruptive”.
The application of this standard has caused considerable angst over the years, with school Principals sometimes allowing what to my eye is a 'heckler's veto' when they forbid some controversial statements because it could cause trouble. The cases as a group don't make a whole lot of sense to me (e.g. no to a T-shirt with a gun, yes to a pro-gay rights shirt, no (mostly) to the confederate flag, and so on). But that's not the point of this story.
One of my sons goes to public school. We were talking this morning on the way in, and we got around to whether people wore Obama or McCain buttons to school.
“We're not allowed to do that,” he said.
My lawyer brain lit up with a big blinking TINKER! sign.
“Why not?” I asked very calmly. (LAWSUIT! LAWSUIT! I'm thinking.)
“Because we're not allowed to have anything sharp, and the buttons have sharp parts [pins] on the back. Teachers can wear them, but we can't.”
“Oh. Would you be allowed to wear a sticker?”
We often hear that law on the sharp end is different from law in the books. Here's a content-neutral prohibition — part of a general zero-tolerance policy on weapons and the like — that I imagine the school could successfully defend as a safety issue in almost any court. And yet it shuts down a whole range of political speech.