HAVING MET LAURIE BEFORE—last year I was paid to help her write a speech on climate change—I knew to expect the eccentric office space and the indiscriminate hey-doll-ing. They are, in a sense, her way of keeping it real—infusing her privileged life with an oddball wit and humility.

But behind Laurie's charm is a confident intelligence, business savvy, and knowledge of issues that, combined with her connections, have made her a promising new force in the world of environmental activists. Robert F. Kennedy Jr., chief prosecuting attorney for Riverkeeper and senior attorney at the Natural Resources Defense Council (NRDC), calls her "one of the most brilliant strategists in today's environmental movement."

Kennedy values, above all, her efforts to bridge the two-party divide on climate issues, despite her loudly proclaimed status as a lifelong Democrat. "She offers a completely new perspective on problem solving, unencumbered by the policy minutiae and partisan bickering of Washington," says Kennedy. "Who else is sitting down with Roger Ailes to discuss climate? Who else is going to the heads of the National Council of Churches and Trout Unlimited, to ranching groups and synagogues and professional women's organizations, and saying, ‘This has got to happen'? Laurie is forging common ground between conservatives and progressives."

Not everyone is impressed. Some dismiss Laurie as another in the long line of celebrities—Barbra Streisand is a favorite target—who consider themselves enlightened enough to tell the masses how to behave, even as they enjoy lavish lifestyles.

"If Laurie David can get the beautiful people of Beverly Hills to give up flying their fuel-guzzling private jets, then I'll pay attention," says Laura Ingraham, conservative radio-talk-show host and author of 2003's Shut Up & Sing, which slams liberal activism by celebs. "What Hollywood doesn't seem to understand is that a significant percentage of Americans don't like what they've done to the culture and have no desire to see them do the same thing to the political landscape."

Indeed, this isn't the first time performers have tried to change the tide of politics. The star-powered environmental campaigns of the late eighties and early nineties, typified by Sting and Ted Danson, may have raised awareness on certain issues—nuclear waste and recycling among them—but they didn't noticeably sway public policy. And while an unprecedented number of celebrities backed Democratic candidate John Kerry in the 2004 presidential election, they failed to deliver a victory.

Motivated by the Bush administration's widely criticized track record on environmental issues, celebrities have once again climbed their soapboxes. But the new crop of glittery greens—led by actors Leonardo DiCaprio and Cameron Diaz—may not fare much better. DiCaprio takes a serious approach, using his role-model status to encourage budding environmentalists through a Web site and public appearances. Last spring, Diaz added entertainment to the mix with Trippin', a short-lived, critically dismissed MTV series that chronicled her adventures with other showbiz pals in environmental trouble spots around the world.

Laurie, however, is not your typical celebrity advocate. For one thing, she's not really a celebrity—or even an actor, despite the common but mistaken assumption that she appears on Curb Your Enthusiasm, a parody of reality TV in which Larry plays himself. Larry's onscreen wife, Cheryl, played by actress Cheryl Hines, does share a few striking similarities with Laurie, and that's no coincidence. Laurie has served as inspiration for both Cheryl and the Elaine Benes character on Larry's other hit show, Seinfeld, and she readily admits that there are blurry lines in her life between entertainment and fact.

The truth, though, is that Laurie has spent more than 20 years behind the camera, not in front of it. "I'm a producer," she says. "I troubleshoot, organize, secure funding, corral talent."

Laurie calls herself an "info fanatic" but doesn't claim to be an expert. Her strength, she feels, is finding new ways to promote the global-warming message. "My job has always been to excite everybody about new talent and to open doors for them," she says. "I'm using exactly the same skills on the environmental issue—to get it out there and to get people seeing what I'm seeing."