NOW to Mondale: unless a woman shares the ticket, Democrats can't win

The message of the 17th annual convention of the National Organization of Women (NOW) was as simple as a three-word slogan: ''Woman VP now.'' That slogan, printed on a two-inch peel-off green sticker, seemed stuck to Miami Beach everywhere: on fronts of dresses, on backs of T-shirts, on handbags, on marble pillars in the lobby of the Fontainebleau Hotel. And it cropped up in every speech and workshop during the three-day conference.

And if Saturday's guest of honor, Walter F. Mondale, somehow missed the stickers, the slogan appeared loud and clear in the welcome he received from 1, 000 members. Chanting ''Run with a woman, win with a woman'' and waving placards reading ''Fritz and a Ms.,'' the group left no doubt about what it expects from the Democratic presidential front-runner at the Democratic convention in San Francisco later this month.

The slogan was also foremost in the keynote address of Judy Goldsmith, national president of NOW. ''Those who are saying that the country isn't ready are precisely wrong,'' she said. ''The country is sending the clearest possible message, and it's our message - it is time for a woman. We aren't saying, 'If there isn't a woman, we won't play.' We're saying, 'If there isn't a woman, we don't win.' ''

To back up her claim that ''women can determine the outcome of the 1984 presidential election,'' Ms. Goldsmith noted that 8 million more women than men are expected to vote in November. And 27 million American women are unregistered , she added.

For Mr. Mondale, who received NOW's endorsement last December, the occasion became an exercise in diplomacy. Despite the courtship, he was careful not to promise a wedding. ''I am considering a number of women, not because they're women but because they're among the best,'' he told the delegates. ''And if I choose a woman, it will be because she is the best.''

Among possible candidates who figured prominently at the conference were Reps. Patricia Schroeder of Colorado, Barbara A. Mikulski of Maryland, and Geraldine A. Ferraro of New York. Mondale is scheduled to meet with Representative Ferraro today.

NOW leaders have promised there will be no walkout at the convention if Mondale chooses a man. The main objective, they emphasized, is to defeat Reagan.