A unanimous U.S. Supreme Court on Friday clarified the circumstances under which a public official’s decision to block someone on social media could trigger legal scrutiny under the First Amendment’s right to free speech.

“When a government official posts about job-related topics on social media, it can be difficult to tell whether the speech is official or private,” Justice Amy Coney Barrett wrote for the court. ”We hold that such speech is attributable to the State only if the official (1) possessed actual authority to speak on the State’s behalf, and (2) purported to exercise that authority when he spoke on social media.”