FIGHTS over free speech in America don’t always produce the loveliest poster children. Gone are the days when intellectuals had to turn to the first amendment as a shield against prosecution for distributing anti-war pamphlets or publishing socialist tracts. In recent decades, fights over the boundaries of protected speech have been waged mainly by racists, anti-Semites, pornographers, dogfight videographers,cross-burners and their kin. The most recent crusader for free speech makes some of these characters look rather tame. Anthony Elonis, whose case the Supreme Court took up on Monday, is challenging his 2011 conviction and prison sentence for a series of Facebook posts a jury determined were “true threats” against his estranged wife, which are not considered protected speech. (As Garrett Epps explains at the Atlantic, the court's conception of a "true threat" isn't a warning that necessarily materialises but an act that has the potential to cause panic or disruption, whether or not the person intends to carry out the threat.) In one post, a 27-year-old Mr Elonis wrote:

If I only knew then what I know now...I would have smothered your ass with a pillow. Dumped your body in the back seat. Dropped you off in Toad Creek and made it look like a rape and murder.

Charming, yes. It gets better:

There's one way to love ya, but a thousand ways to kill ya, And I'm not going to rest until your body is a mess, Soaked in blood and dying from all the little cuts. Hurry up and die bitch.

We should forgive Justice Antonin Scalia for saying to an agreeable Michael Dreeben, the government’s lawyer, that “this language is not worth a whole lot anyway, right?” Freedom of speech is enshrined in the first amendment to facilitate robust debate and discussion essential to democratic self-government. It serves as a bulwark against government encroachment on individual expression. It offers a safe harbour against laws or officials seeking to punish dissenters or silence unpopular views. So it’s hard to fathom what value the Founding Fathers would see in Mr Elonis’s vivid threats. The petitioner’s wife, Tara, certainly did not care for this form of personal expression. She secured a protection-from-abuse order against Mr Elonis in 2010, prompting him to craft still more abusive Facebook posts, against her and against schoolchildren and an FBI agent. This cascade led to the criminal charges, the conviction and 44 months in prison.

In reaching its verdict in the trial, the federal jury was asked to consider whether Mr Elonis’s posts would be viewed by a reasonable observer as serious plans to inflict harm. This is the test in use in most of the country, but two federal districts and some states opt for a subjective standard asking whether the person expressing himself actually intended the statement as a threat to cause another person harm. In his brief to the justices and in the hearing on Monday, Mr Elonis denied ever intending harm. He penned the posts, he claims, as “therapeutic” exercises to handle his angst in the wake of being abandoned by his wife. The missives may have been rather crude and bloody-sounding, but they were just words—harmless and worthy of constitutional protection.

The exchange on Monday was lively, with multiple views bandied about on which characteristics and what level of knowledge should be attributed to a hypothetical "reasonable person". Everyone seemed to be grasping for a definition of what kind of language may be clearly seen as threatening, either through intent or interpretation. Several justices paused to admit confusion about what each lawyer was really arguing. The jurist who stepped in to clearly sketch the possible lines of argument was, as usual, Elena Kagan. Here is her exchange early on with John Elwood, Mr Elonis’s lawyer:

JUSTICE KAGAN: Mr Elwood,...I'm trying to figure out what exactly the level of intent you want is. So one, the very, very highest level might be I affirmatively want to place this person in fear; that's why I'm doing what I'm doing. All right? There's a step down from that which is: I don't want to do that; I'm just fulfilling my artistic fantasies, whatever you want to call it; but I know that I am going to place this person in fear. All right? Is that what—which intent do you want? MR ELWOOD: The second...That if you know that you are placing someone in fear by what you are doing, that is enough to satisfy our version of— JUSTICE KAGAN: How about you just take it a step down more but not get to the government's. How about if you don't know to a certainty, but you know that there is a substantial probability that you will place that person in fear, which is what I take it we would usually mean when we talk about recklessness?

This “recklessness” standard, whereby someone could be convicted as long as he knew that his speech would be frightening, even if he didn’t actually intend it as a threat, garnered little support from either attorney. Mr Elwood said it would offer no protection for mouthy teenagers “shooting off their mouths or making...ill­-timed, sarcastic comments which wind up getting them thrown in jail.” On the other side, Mr Dreeben worried that a recklessness test “basically immunises somebody who makes [a threat] and then can plausibly say later, 'hey, I was dead drunk, I realized that I just called in a bomb threat and the police had to respond and an elementary school had to be evacuated and I knew what I was saying but I was too drunk'” to understand that someone might take it seriously. Samuel Alito was clearly unsympathetic to Mr Elonis’s claims; he called the abusive husband’s I’m-just-venting-and-composing-rap-lyrics defence a “roadmap for threatening a spouse and getting away with it.” But few of the other justices gave a clear indication of how they might vote.

Late in the hearing, Justice Kagan again offered a clarion explanation of what is at stake in Mr Elonis’s first-amendment challenge:

JUSTICE KAGAN: Mr Dreeben, you are asking us to go down ­­you know, it's not purpose, it's not knowledge of causing fear, it's not a conscious disregard of causing fear, it's just that you should have known that you were going to cause fear, essentially. And that's not the kind of standard that we typically use in the First Amendment...[W]e typically say that the First Amendment requires a kind of a buffer zone to ensure that even stuff that is wrongful maybe is permitted because we don't want to chill innocent behavior.

This is the core of the matter. As nasty as Mr Elonis’s Facebook posts may have been, the question is what happens in future cases when the government seeks to punish people for venting or trying their hand at some gangsta rap on their Facebook pages. What, Chief Justice John Roberts asked, distinguishes Mr Elonis’s diatribes from Eminem’s multi-platinum records, in which he speaks in excruciatingly violent terms about what he'd like to do to his wife? The main distinction, according to Mr Dreeben, is that Eminem’s lyrics are delivered “at a concert where people are going to be entertained.”

There is a plausible argument to be made that domestic violence prosecutions would be hindered by a ruling that protects Mr Elonis’s antics, but this isn’t the only consideration the justices must weigh. Why should abusive speech that entertains an audience enjoy constitutional protection while Mr Elonis’s amateurish attempts to mimic Eminem be judged beyond the pale? It is a tough question the justices will attempt to answer in a few months.