Andy Martin, a West Palm Beach lawyer and perennial candidate for various political offices, is running the ad on WMUR-TV, an ABC affiliate that has aired presidential debates.

The Bush campaign said it had not asked WMUR to stop running the ad. Spokesman Ari Fleischer said WMUR would have to decide that on its own.

"It's part of the unfortunate nonsense that can come with political campaigns," Fleischer said. "These things are as mean-spirited as they are inaccurate."

WMUR spokeswoman Julie Campasano, who handles media inquiries about the station's advertising policies, said the station never considered witholding the ad.

"It wasn't even an issue. The law is the law," she said today. "The FCC says clearly, a legally qualified candidate can say whatever they want to say in their message, and we as a station have no authority, permission or right to censor or otherwise edit any of the spots."

A Federal Communications Commission official said today the station had no choice but to accept the ad.

"Even if the stations being given this ad know for a certainty this information is false, because of the `no censorship' provision in the equal time law, they have no choice but to run it," said Bobby Baker, the commission's chief of political programming.

Courts have ruled that broadcasters cannot be held liable for running false ads, he said.

"The broadcaster is insulated from responsibility, but that does not mean this candidate cannot be sued," he said.

Baker said in the early 1990s, the commission allowed stations to decide when to air ads they found offensive. For example, ads that featured graphic images of abortions were aired late at night, he said.

But courts have since ruled that such scheduling itself is an act of censorship, he said.

In the ad, Martin alleges: "George Bush had a cocaine problem. His brain suffered from alcohol abuse. Don't trust Bush with your vote until he trusts you with the truth about his past."

Bush has refused to answer some questions about his past, saying only that he has not used illegal drugs since 1975. No evidence has surfaced that he ever used cocaine.

Martin began airing commercials in New Hampshire before Thanksgiving, calling himself "New Hampshire's favorite son for president."