NEW YORK — At a cocktail reception last fall, Rep. Don Edwards (D-San Jose) introduced a tall, dark-haired woman standing in a corner as Nancy Pelosi and thanked her for attending the opening of a California think tank in Washington. But Pelosi, it turned out, never showed at the event.

What then was an innocent case of mistaken identity would be considered a major faux pas today. Pelosi, a longtime political activist and party insider before being elected to Congress in 1987, has emerged from relative obscurity to become one of the Democrats' rising national stars.

She has played a key role as co-chair of the Democratic Party Platform Committee in proposing solutions to the nation's economic, environmental and social problems that Democrats hope will help them take over the White House. And her name was mentioned by pundits and the press as a potential candidate for vice president, though Pelosi never took the talk seriously.

Tonight, Pelosi will be given a prominent role on the convention stage when she delivers a speech and presides over proceedings to adopt the party platform, called "A New Covenant with the American People."

The 22-page policy manifesto is designed to give the party a more centrist image in the mold of presumptive Democratic nominee Bill Clinton. But Pelosi, pursuing the liberal interests of her San Francisco constituents, pushed hard for platform language that declares a "war on AIDS" and reaffirms public support for the National Endowment for the Arts without "political manipulation."

"AIDS is a paramount issue in my district," Pelosi said. "That was a high priority for me, and I think the strong language that is in the platform is as strong as it is because of my role."

Pelosi's ascent on the national scene comes at a time when other California women--from Senate candidates Barbara Boxer and Dianne Feinstein to state Treasurer Kathleen Brown--are generating enthusiasm among delegates here. This week's convention, Pelosi said, is being used by women candidates as a staging ground to achieve political influence in years to come.

"I think this is the year of the woman the way 1776 was the year of our country's declaration," Pelosi said in an interview. "I feel quite certain that it's real and it has staying power and it's going to change public policy forever."