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

They were skeptical as they weighed arguments in the Western Pennsylvania 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.

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.

Stevens was convicted in federal court in Pittsburgh in 2005 on three counts of distributing depictions of animal cruelty. .

The Third U.S. Circuit Court of Appeals overturned the conviction, finding that the 1999 law - which banned the sale and distribution of all visual depictions of animal cruelty - violated the First Amendment right to free speech.

Free-speech supporters have argued that the statute could be misapplied and used to censor hunting magazines and documentaries on subjects ranging from American Indian history to animal cruelty.

Deputy Solicitor General Neal Katyal said the original goal of Congress in passing the law was to end crush videos. Katyal said the law was effective; since it was enacted, no one has been prosecuted for a crush video.

The justices repeatedly asked each side if, under the law, 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, or the stuffing of geese to make foie gras.

Justice Samuel Alito asked if the government could prohibit the production and sale of videos depicting gladiators battling to the death, or whether Congress could restrict a "human-sacrifice" television channel.

Patricia Millett, Stevens' attorney, was repeatedly asked the question about the human-sacrifice channel. She failed to answer it directly.

"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."

Millett argued it is not up to Congress to shield the public's eyes. Further, she said that the law, which has been compared with legislation against 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 practice of dogfighting would continue, she said.

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."

A decision is expected by spring.

The case is U.S. v. Stevens, 08-769.