WASHINGTON (AP) — Broadcasters anticipating a major constitutional ruling on the government's authority to regulate what can be shown and said on the airwaves instead won only the smallest of Supreme Court victories Thursday.

The justices unanimously threw out fines and other penalties against Fox and ABC television stations that violated the Federal Communications Commission policy regulating curse words and nudity on television airwaves.

Forgoing a broader constitutional ruling, however, the court concluded only that broadcasters could not have known in advance that obscenities uttered during awards show programs on Fox stations and a brief display of nudity on an episode of ABC's "NYPD Blue" could give rise to penalties. ABC and 45 affiliates had been hit with proposed fines totaling nearly $1.24 million.

Broadcasters had argued that the revolution in technology that has brought the Internet, satellite television and cable has made the rules themselves obsolete. The regulations apply only to broadcast channels.

The justices said the FCC is free to revise its indecency policy, which is intended to keep the airwaves free of objectionable material during the hours when children are likely to be watching.

The agency's chairman, Julius Genachowski, said the ruling "appears to be narrowly limited to procedural issues related to actions taken a number of years ago. Consistent with vital First Amendment principles, the FCC will carry out Congress's directive to protect young TV viewers."

It was the second time the court has confronted, but not ruled conclusively on the FCC's policy on isolated expletives. Justice Anthony Kennedy said in his opinion for the court that "it is unnecessary for the court to address the constitutionality of the current policy."

The narrow decision, coupled with the more than five months that elapsed between the argument in January and Thursday's decision, could mean that the justices struggled and failed to reach agreement on a broader outcome.

Broadcasters argue that viewers now have many options, unlike the handful of channels they had available in the 1960s and 1970s when the court last weighed in on indecency on the airwaves. In many cases, viewers don't even know when they are switching between the older broadcast channels and cable.

Still, the regulated broadcast channels provide what the government has called a safe haven of milder programming, and those channels remain dominant, even in the Internet age, the administration argued.

Paul Smith, a First Amendment expert and partner with the Jenner and Block law firm in Washington, said the court should expect more challenges until it rules definitively.

"The Supreme Court decided to punt on the opportunity to issue a broad ruling on the constitutionality of the FCC indecency policy. The issue will be raised again as broadcasters will continue to try to grapple with the FCC's vague and inconsistent enforcement regime," said Smith, who wrote a brief supporting the broadcasters.

The case arose from a change in the FCC's long-standing policy on curse words.

For many years, the agency did not take action against broadcasters for one-time uses of curse words. But after several awards shows with cursing celebrities in 2002 and 2003, the FCC toughened its policy after it concluded that a one-free-expletive rule did not make sense in the context of keeping the airwaves free of indecency when children are likely to be watching television.

But Kennedy, in the ruling throwing out the fines, said the commission did not adequately explain that under the new policy "a fleeting expletive or a brief shot of nudity could be actionably indecent."

The stepped-up indecency enforcement, which included issuing record fines for violations, also was spurred in part by widespread outrage following Janet Jackson's breast-baring performance during the 2004 Super Bowl halftime show on CBS.

That incident and the FCC's proposed fine of $550,000 are not part of the current case. The government has an appeal pending of a lower court ruling that threw out the fine in that case.

The 2004 Super Bowl took place before the FCC later that year laid out its new policy and the possibility of fines for even one-time utterances of certain words.

Tim Winter, president of the Parents Television Council, said he read the new decision as a "green light" for the FCC to rule against broadcasters in the many pending complaints of indecent material that aired after the FCC explained its new policy.

"Once again the Supreme Court has ruled against the networks in their yearslong campaign to obliterate broadcast decency standards," Winter said.

The material at issue in Thursday's decision included the isolated use of expletives as well as fines against broadcasters who showed a woman's nude buttocks on a 2003 episode of "NYPD Blue."

In December 2002, singer Cher used the phrase "F--- 'em" during the Billboard Music Awards show on the Fox television network. A month later, U2 lead singer Bono uttered the phrase "f------ brilliant" during NBC's broadcast of the Golden Globes awards show. During the December 2003 Billboard awards show on Fox, reality show star Nicole Richie said, "Have you ever tried to get cow s--- out of a Prada purse? It's not so f------simple."

But the challenge went beyond just the penalties for the use of fleeting expletives.

The broadcasters wanted the court to free them from all regulation of content around the clock. The court's 1978 Pacifica decision upheld the FCC's reprimand of a New York radio station for airing a George Carlin monologue containing a 12-minute string of expletives in the middle of the afternoon.

Justice Ruth Bader Ginsburg said in a brief opinion that she would have overturned the Pacifica ruling, which she called wrong even when it was decided. Justice Sonia Sotomayor did not take part in the current case because she was involved in an earlier version while sitting as an appeals court judge in New York.

The case is FCC v. Fox, 10-1293.