WASHINGTON – The Supreme Court spent an hour on Tuesday talking about dirty words on television without once using any or making plain how it would decide whether the government could ban them.

The dispute between the broadcast networks and the Federal Communications Commission is the court’s first major broadcast indecency case in 30 years.

At issue is the FCC’s policy, adopted in 2004, that even a one-time use of profanity on live television is indecent because some words are so offensive that they always evoke sexual or excretory images. So-called fleeting expletives were not treated as indecent before then.

The words in question begin with the letters “F” and “S.” The Associated Press typically does not use them.

Chief Justice John Roberts, the only justice with young children at home, suggested that the commission’s policy is reasonable. The use of either word, Roberts said, “is associated with sexual or excretory activity. That’s what gives it its force.”

Justice John Paul Stevens, who appeared skeptical of the policy, doubted that the f-word always conveys a sexual image.

“Isn’t it true that that is a word that often is used with no reference whatsoever to the sexual connotation?” he asked.

Fox Television Stations, owned by Rupert Murdoch’s News Corp., and other networks challenged the policy after the FCC singled out use of the words by Bono, Cher and Nicole Richie during awards programs that were aired in 2002 and 2003.

In each instance, a variation of the f-word was used either as a modifier — as in Bono’s comment that an award was “really f—ing brilliant” — or as a metaphor, as when Cher said, “F— ’em,” to her critics.

A federal appeals court in New York threw out the ban, saying the FCC didn’t provide enough explanation, and the government appealed to the Supreme Court. The appeals court also said, but did not rule, that the new policy probably is unconstitutional.

The court could avoid deciding whether the FCC policy violates the Constitution and instead determine that the FCC did not adequately explain the need for the new policy.

It was hard to tell where the court is heading because three justices — Samuel Alito, Anthony Kennedy and Clarence Thomas — said little or nothing.

When the court ruled 30 years ago that the FCC could keep profanities off the airwaves between 6 a.m. and 10 p.m., television broadcasts were the only source of images available to most Americans.

Today, the Internet, cable and satellite television are in millions of homes, yet the FCC’s authority extends only to broadcast television and radio.

Solicitor General Gregory Garre, the Bush administration’s top Supreme Court lawyer, said that despite the explosion of options, “most Americans still get their information and entertainment from broadcast TV.”

Garre said a broad ruling against government regulation of broadcast indecency would create a world where anything goes.

In an admittedly extreme example, Garre said, children could see “Big Bird dropping the F-bomb on Sesame Street.”

Carter Phillips, Fox’s lawyer, said that increased usage of profanity was unlikely no matter how the court ruled. Apart from unscripted incidents on live television, broadcasters do not permit the use of certain words on television, even during late-night hours when they are free to do so.

He urged the justices to strike down the policy as an unconstitutional restriction on the networks’ free speech rights.

C-SPAN asked the court to release a recording of the arguments for airing shortly after their conclusion. The court grants such requests from time to time, but turned down C-SPAN with no explanation.