That’s what the U.S. Supreme Court aims to determine. The country’s highest court said Monday it will hear the case of Anthony Elonis, a Pennsylvania man convicted in 2010 of making criminal threats of violence against his estranged wife, an FBI agent and others via his Facebook account.

Two lower courts have ruled that Elonis crossed the line into criminal behavior when he discussed killing his wife in a series of messages posted on his Facebook (FB) page, which were often written in the form of rap lyrics. Elonis has compared his messages to the rap lyrics of artists such as Eminem while contending that the content never rose to the level of a true threat, because he never intended to actually commit any violent acts.

The crux of the case, and what the Supreme Court must decide, is whether a conviction for threatening someone depends on “the defendant’s subjective intent to threaten,” or if, as the lower courts ruled, it is enough to prove that “a reasonable person” would feel threatened by the Facebook posts. The Supreme Court has said in the past that “true threats” of violence are not protected under the First Amendment, but the dispute over what constitutes a genuine threat has been raging since the Supreme Court ruled in the 2003 case Virginia v. Black that cross-burning is not always meant as a form of intimidation and should therefore be considered protected speech.

Last year, a federal appeals court upheld Elonis’ 2010 conviction, which ruled “that a reasonable jury could find the [Elonis’ statements] to be a true threat.”