The U.S. Supreme Court will hear a groundbreaking case on Monday regarding whether death threats posted on Facebook and other social media are protected by a person’s First Amendment rights to free speech. It will be the first time the justices weigh in on the topic.

The case before the court centers around Anthony Elonis, who in 2010 was sentenced to 3 1/2 years in prison for posting threatening statements on Facebook against his wife, former employer and coworkers, nearby schools and an FBI agent who investigated him. Elonis argued at trial that the threats were not serious and merely a therapeutic way for him to deal with the pain of his divorce.

Any decision by the court could have far-reaching consequences in the world of social media, where posted comments are often hasty and not well thought out. The Supreme Court has said for more than four decades that “true threats” of harm to another person are not protected under Constitutional rights to free speech.

The central question will be whether the speaker’s point of view or the listener’s matters most. When Elonis was convicted the jury was instructed to consider whether it was reasonable that his wife would interpret his Facebook threats to harm her as serious. The Supreme Court will determine whether to uphold the ruling or convict only if jurors consider the intent to harm another person as serious. The question is whether one person’s freedom to express violent threats overrides another person’s freedom to live without fear of harm.

Civil liberties advocates such as the A.C.L.U. want the court to look at intent before criminalizing speech. In a brief filed in the Elonis case the groups said they did not think the question of whether a statement made on social media is threatening should be determined solely by the reader.