Imagine that a public high school student posts an editorial cartoon criticizing efforts to expand the Supreme Court on his Facebook page. The next day, when the student arrives at school, administrators pull him aside. They tell the student that because of his post, his classmates are debating court-packing when they should be studying algebra. The administrators give the student an ultimatum: Delete the Facebook post or face school discipline.

This might seem like a blatant invasion of the student’s First Amendment right to speak out on matters of public concern. Yet, it could be allowed if the Supreme Court rules for a Pennsylvania school district in a case argued this Wednesday called Mahanoy Area School District v. B.L.