Thousands of commercials for vodka, rum or whiskey have run on cable and local TV since the trade organization for liquor marketers decided in 1996 to lift a voluntary ban on television advertising.

But NBC became the first major national broadcast network to air such ads when on Dec. 15 it ran a Smirnoff vodka ad promoting designated drivers. Before airing product-specific commercials, distilled liquor companies must air ads promoting responsible drinking for four months.

Opponents of NBC's decision include members of Congress and federal regulators, the American Medical Association, and advocacy groups like the Center for Science in the Public Interest (CSPI). Concerned about ever-growing exposure of children to liquor ads, they are calling for the federal government to intervene.

"Self-regulation isn't working," said Joseph A. Califano Jr., president of the National Center on Addiction and Substance Abuse at Columbia University in New York. "We need legislation or rules from the Federal Communications Commission."

George Hacker, director of the Alcohol Policies Project at CSPI in Washington, noted that as the network becomes "the subject of mounting public criticism and pressure, the potential for hearings is good."

Not surprisingly, the liquor industry doesn't see a need for federal regulation. "It is important for us to be on television, to be recognized as part of a healthy, normal lifestyle for those who choose to drink," said Peter H. Cressy, CEO of the Distilled Spirits Council in Washington.

Even popular culture has taken notice of the public anger, with the comic strip "Doonesbury" and Jay Leno taking shots at the NBC decision.

The complaints have apparently prompted NBC and Guinness to limit the first ad's appearance to after 11:30 p.m., although NBC's current rules allow for liquor ads after 9 p.m.

NBC has also signaled that it may be willing to revisit its guidelines to limit the exposure and attractiveness of liquor ads to children. "We're not pretending we have all the answers," said Randy Falco, president at the NBC Television Network. "The standards are a living, breathing document. If something is out of context, we change it."

If all four national broadcast networks aired liquor ads, they could rake in $300 million -- a fraction of the $12 billion to $14 billion in annual ad revenue, but a significant amount during the advertising market's worst downturn in decades.