WASHINGTON -- Supreme Court justices discussed topics ranging from dogfights to traditional fox hunting to a hypothetical human sacrifice television channel yesterday in their questioning of attorneys over a law aimed at animal cruelty videos.

They were skeptical as they weighed arguments in the case over the 10-year-old law that bans the production and sale of the videos.

A federal appeals court struck down the statute and invalidated the conviction of Robert J. Stevens of Pittsville, Va., who was sentenced to three years in prison for videos he made about pit bull fights. The government appealed, and the Supreme Court agreed to review the decision in the widely watched case over a law originally meant to curtail "crush" videos that show high-heeled women stomping on small animals.

During the hour-long session, the justices repeatedly raised hypothetical examples -- some of them extreme -- as they prodded lawyers to parse the law, which animal rights supporters say is absolutely necessary but First Amendment advocates say is a quick step down a slippery slope toward censorship and viewpoint discrimination.

Mr. Stevens was convicted in Pittsburgh in 2005 on three counts of distributing depictions of animal cruelty. A pit bull enthusiast, he sold videos about the breed that included scenes of dogfighting -- though they were filmed either in Japan, where the act is legal, or in the United States before dogfighting was outlawed.

In a full-panel decision, the 3rd U.S. Circuit Court of Appeals overturned the conviction, finding that the 1999 law in question -- which banned the sale and distribution of all visual depictions of animal cruelty -- violated the First Amendment right to free speech.

The dogfight argument was the first of the day and fourth of the court's new term. Assistant U.S. Attorney Stephen R. Kaufman, who prosecuted the original case, sat at the government counsel table. Also in the courtroom were U.S. Attorney Mary Beth Buchanan, Mr. Stevens' federal public defender, Michael J. Novara, and Third Circuit Judges Thomas M. Hardiman and D. Michael Fisher.

Newcomer Justice Sonia Sotomayor posed the first question of the day, asking Deputy Solicitor General Neal Katyal about the congressional intent of the law.

Free speech supporters have argued that the statute could be misapplied and used to censor hunting magazines, documentaries on a wide range of subjects from Native American history to animal cruelty and anything in between.

But Mr. Katyal said the original goal of Congress in passing the 1999 law was a deluge of some 3,000 "crush videos," used by sexual fetishists, that had been circulating..

The government argued that the intent of the law was to dry up that market.

In answering a question by Justice Ruth Bader Ginsburg, Mr. Katyal admitted that the law has never been used to prosecute anyone for a crush video. He added that it's because the law worked so well.

But the justices repeatedly asked each side if under the law in question, certain images could be prosecuted. Justice Antonin Scalia spoke about bullfighting. Justice Stephen Breyer raised other examples -- quail hunting; the slaughter of animals; deer or bear hunting; as well as the stuffing of geese to make fois gras.

Mr. Katyal tried to alleviate those concerns by stating the history of the statute.

"We have had 10 years of experience, Justice Breyer, under the statute, and we haven't seen those things being chilled."

He warned the court not to get caught up in what could happen.

"But what this court has said is that ... we should be careful about that endless stream of fanciful hypotheticals."

His warning did not stop Justice Samuel Alito from asking if the government could prohibit the production and sale of videos depicting gladiators battling to the death.

Justice Alito asked whether Congress could restrict a "human sacrifice" television channel.

Mr. Katyal responded that the gladiator videos could fall under one of the several exemptions provided under the law and therefore be protected by the First Amendment.

Justice Scalia remarked: "If you dress up like an ancient Roman, the whole thing is of historical interest? Is that it?"

Patricia Millett, the attorney for Mr. Stevens, was repeatedly hit with the question about the human sacrifice channel. She failed to answer it straight on.

"The fact that conduct is repulsive or offensive does not mean we automatically ban the speech," she said.

"I think at some level Congress has a job to write with a scalpel and not a buzz saw in the First Amendment area."

Chief Justice John Roberts asked Mr. Katyal why animal rights groups that use images of cruelty to raise awareness and funds are not subject to prosecution.

"...Congress carved a broad exemption in Section 48 precisely to make sure that expressive messages aren't swept up," Mr. Katyal said.

But continuing along the same line, Justice Sotomayor asked about a documentary on dogfighting. Though its producer was not prosecuted, the film contained much more graphic images than Mr. Stevens', she said.

"Doesn't there have to be a judgment inherent in this statute?" she asked.

"The line will sometimes be difficult to draw, just as it's difficult to draw in child pornography," Mr. Katyal responded.

Justice Sotomayor quickly cut him off.

"But it's not in child pornography because, there, Congress says the very act -- it doesn't matter how artistic it is. That very act of child pornography is illegal."

Ms. Millett argued it is not up to Congress to shield the public's eyes. Further, she said that the law in question, which has been compared to child pornography, is different in a number of ways. In child pornography, the demand for it drives production. Even if every dogfighting video in the country were thrown away tomorrow, the act of dogfighting would continue, she said.

"You've got to prove causation, that these images cause the harm. ... You also have got to prove that Congress is acting in an evenhanded way."

In his short rebuttal, Mr. Katyal suggested that the court use its decision to add nuance to the statute and make it clear what visual depictions would fall outside of the law's reach.

Earlier, Justice Breyer wondered why the original law wasn't written more clearly.

"Why not do a simpler thing? Rather than let the public guess as to what these words mean, ask Congress to write a statute that actually aims at those frightful things that it was trying to prohibit. Now that can be done. I don't know why they couldn't do it."

Washington correspondent Daniel Malloy writes the "Pittsburgh On The Potomac" blog exclusively at PG+, a members-only web site of the Pittsburgh Post-Gazette. Our introduction to PG+ gives you all the details.