The decision set new limits on disciplining students for off-campus speech but did not totally bar administrators from doing so.

WASHINGTON — The Supreme Court ruled on Wednesday that a Pennsylvania school district had violated the First Amendment by punishing a student for a vulgar social media message sent while she was not on school grounds. The decision, on a vote of 8 to 1, did not establish a categorical ban on regulating student speech outside of school, citing the need of school systems to be able to deal with issues like bullying and threats. Instead, it set out factors that courts should assess in weighing the right of administrators to punish speech in nonschool settings, with one important component being whether parents are better suited to handle the situation. But it was the first time in more than 50 years that a high school student won a free-speech case in the Supreme Court, and the decision emphasized that courts should be skeptical of efforts to constrain off-campus speech.