The Supreme Court is preparing to hear arguments on a case that may determine the future of free expression on the internet.

The case centers on remarks posted on Facebook by Anthony Elonis. The would-be rapper said he wanted to kill his estranged wife, kill an FBI agent, and shoot up a kindergarten class.

Elonis was subsequently convicted and sentenced to four years in prison for violating a federal statue that makes it illegal to threaten another person.

In his defense, Elonis argues the remarks were not serious. He says the lyrics were a form of spontaneous expression and he had no intention of harming his wife or an FBI agent who visited him to determine if he was a threat.

First Amendment advocates say a lower court ruling on the Elonis case threatens freedom of expression.

"A statute that proscribes speech without regard to the speaker's intended meaning runs the risk of punishing protected First Amendment expression simply because it is crudely or zealously expressed," states a brief from the American Liberties Union and other groups.

The Supreme Court has consistently ruled that a "true threat" depends on how speech is perceived by an "objective" person.

The Court says language perceived as threatening is not protected under the First Amendment. It has drawn a line between political hyperbole and verbal attacks on individuals.

Murray Rothbard and other advocates of the Non-Aggression Principle believe speech does not represent a true threat.