Mom couldn't get you to drink your milk, but Madonna might.

At least that's what a big-time New Jersey dairyman and an outgoing Minnesota senator hope.They're trying to persuade the dairy industry to levy a tax on itself to finance a multimillion-dollar advertising war with the soft drink industry.

Skeptics, such as Agriculture Secretary Clayton Yeutter, believe Americans already drink as much milk as they're going to.

But Marc Goldman, who runs an independent dairy in the New York City area, and Sen. Rudy Boschwitz, R-Minn., say milk's problem isn't that Americans don't want to drink it, but that they haven't been sold on it.

"If your mother tells you to drink milk and Madonna tells you to drink soda, Madonna wins most of those arguments," Goldman said. "We've got to get Madonna and others like her on our side."

At Boschwitz' initiative, the 1990 farm bill passed by Congress authorizes the government to collect a tax of 20 cents per 100 pounds of milk, if a majority of the nation's milk processors approve of it in a referendum. No vote has yet been scheduled.

The assessment would work out to about 1 1/2 cents a gallon. Processors could take it out of their profits or pass it on to consumers.

Soft-drink manufacturers spend $500 million a year hawking their product, while dairy farmers invest a relatively meager $60 million, Goldman said. So it's no wonder to him that U.S. milk consumption has fallen markedly over the past two decades.