WASHINGTON — The Supreme Court today stepped into a legal fight over the use of curse words on the airwaves. It is the high court's first major case on broadcast indecency in 30 years.

The case concerns a Federal Communications Commission policy that allows for fines against broadcasters for so-called "fleeting expletives," one-time uses of the F-word or its close cousins.

Fox Broadcasting Co., along with ABC, CBS and NBC, challenged the new policy after the commission said broadcasts of entertainment awards shows in 2002 and 2003 were indecent because of profanity uttered by Bono, Cher and Nicole Richie.

The 2nd U.S. Circuit Court of Appeals court said the new policy was invalid and could violate the First Amendment.

No fines were issued in the incidents, but the FCC could impose fines for future violations of the policy.

The case before the court technically involves only two airings on Fox of the "Billboard Music Awards" in which celebrities' expletives were broadcast over the airwaves. NBC is separately challenging an FCC decision that rapped the network for airing Bono's use of the F-word during a Golden Globes awards show in 2003.

The case, FCC v. Fox Television Stations, 07-582, will be argued in the fall.

The FCC appealed to the Supreme Court after the 2nd U.S. Circuit Court of Appeals in New York nullified the agency's enforcement regime regarding "fleeting expletives." By a 2-1 vote, the appeals court said the FCC had changed its policy and failed to adequately explain why it had done so.

The appeals court, acting on a complaint by the networks, nullified the policy until the agency could return with a better explanation for the change. In the same opinion, the court also said the agency's position was probably unconstitutional.

The court rejected the FCC's policy on procedural grounds, but was "skeptical that the commission can provide a reasoned explanation for its fleeting expletive regime that would pass constitutional muster."

Solicitor General Paul Clement, representing the FCC and the Bush administration, argued that the decision "places the commission in an untenable position," powerless to stop the airing of expletives even when children are watching.

The FCC has pending before it "hundreds of thousands of complaints" regarding the broadcast of expletives, Clement said. He argued that the appeals court decision has left the agency "accountable for the coarsening of the airwaves while simultaneously denying it effective tools to address the problem."

The appeal also argued that the FCC's explanation of its policy was well reasoned and that the appeals court decision was at odds with the landmark 1978 indecency case, FCC v. Pacifica Foundation, the last broadcast-indecency case heard by the Supreme Court.

Lawyers for the networks said the old policy worked well for 30 years and that broadcasters had no reason suddenly to allow for an explosion of expletives.

Separately, CBS is challenging a $550,000 fine the FCC imposed for the "wardrobe malfunction" that bared Janet Jackson's breast during a televised 2004 Super Bowl halftime show. The 3rd U.S. Circuit Court of Appeals in Philadelphia is considering whether the incident was indecent or merely a fleeting and accidental glitch that shouldn't be punished.

The case is the second recent test of the federal government's powers to regulate broadcast indecency. Last June, a federal appeals court in New York invalidated the government's policy on fleeting profanities uttered over the airwaves.

The new policy was put in place after a January 2003 broadcast of the Golden Globes awards show by NBC when U2 lead singer Bono uttered the phrase "f------ brilliant." The FCC said the "F-word" in any context "inherently has a sexual connotation" and can trigger enforcement.

The Fox programs at issue are a Dec. 9, 2002, broadcast of the Billboard Music Awards in which singer Cher used the phrase "F---'em" and a Dec. 10, 2003, Billboard awards show in which 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."