When does an online threat become worthy of criminal prosecution?

The Supreme Court is being asked to decide that unanswered question as prosecutions for online rants, from Facebook to YouTube, are becoming commonplace. Authorities are routinely applying an old-world 1932 statute concerning extortion to today's online world, where words don't always mean what they seem.

The latest case involving the legal parameters of online speech before the justices concerns a Pennsylvania man sentenced to 50 months in prison after being convicted on four counts of the interstate communication of threats. Defendant Anthony Elonis' 2010 Facebook rant concerned attacks on an elementary school, his estranged wife, and even law enforcement.

"That's it, I've had about enough/ I'm checking out and making a name for myself/ Enough elementary schools in a ten mile radius/ to initiate the most heinous school shooting ever imagined/ and hell hath no fury like a crazy man in a Kindergarten class/ the only question is … which one?" read one of Elonis' posts.

It won't be the first time the justices have been asked to resolve the issue.

That's because there are regularly fresh media accounts of defendants handed lengthy prison terms for their online speech. Weeks ago, for example, another Pennsylvania man was handed up to a six-year term for a YouTube rap video threatening police officers.

In the Elonis case pending before the Supreme Court, the 30-year-old contends that the authorities never proved he intended to threaten anybody. But a federal appeals court in September ruled that the standard of proof is whether a reasonable person—the target of the rant—would deem the online speech threatening.

So the Third US Circuit Court of Appeals upheld Elonis' sentence and conviction. He appealed to the Supreme Court.

Whatever a so-called "true threat" is, it's not protected under the First Amendment. Whether online or not, other forms of speech that do not enjoy the backing of the constitution include child pornography and obscenity.

The Supreme Court a decade ago described true threats in a Virginia cross burning decision as "statements where the speaker means to communicate a serious expression of an intent to commit an act of unlawful violence to a particular individual or group of individuals."

Clay Calvert, a scholar at the University of Florida in Gainesville, notes that the court has never considered the issue in the online context.

"Will people discount or treat less seriously speech posted on Facebook or a video uploaded to YouTube than they would in person or in a traditional medium such as newspapers or television? The Court never has considered how the nature of online media affects a true threats analysis," he wrote.

In his petition to the Supreme Court, Elonis' counsel said the issue boils down to "whether a person can be convicted of the felony 'speech crime' of making a threat only if he subjectively intended to threaten another person, or whether instead he can be convicted if he negligently misjudges how his words will be construed and a 'reasonable person' would deem them a threat."

Only one federal appeals court has sided with Elonis' contention that the authorities must prove that the person who made the threat actually meant to carry it out. Eight other circuit courts of appeal, however, have ruled that the standard is whether a "reasonable person" would conclude the threat was real.

It won't be the first time the justices faced a case asking the same questions as presented in Elonis' petition.

The high court, without ruling, last year let stand an 18-month term handed to an Iraqi war veteran who prosecutors said posted a 2010 YouTube video threatening to kill a Tennessee judge unless the judge granted visitation rights to his daughter. Defendant Franklin Jeffries II said he never intended to carry out the threat, but the justices declined to review his case.

The Obama administration has until April 21 to respond to Elonis' petition to the Supreme Court. In the veteran's case, however, the administration urged the high court to reject the case (PDF).

"Although some disagreement exists among the courts of appeals on the question of whether proof of a true threat requires proof of a subjective intent to threaten, review of that question is not warranted because the circuit split is shallow and may resolve itself without this Court’s intervention and because any error was harmless," the government wrote to the justices while urging them to reject the case.