(FORTUNE Small Business) – Mmm, that's good!" says Mark Walsh, dipping into a bowl of guacamole at Rosa Mexicana in Washington, D.C. "So fresh!" He likes it chunky too: "When the guacamole has been through the strainer, I hate that." Walsh could be talking about his vision for Air America, the new liberal radio network that went live March 31 in Chicago, Los Angeles, and New York: fresh content, unfiltered, a lot to chew on.

Is there really an appetite for such fare? Walsh, 49, CEO of Air America's parent, Progress Media, and his co-investors think so. They're betting $30 million that aggressive, opinionated, topical talk radio--the house that Rush built--has a heretofore hidden left wing. They've signed Saturday Night Live alum Al Franken, author of Rush Limbaugh Is a Big Fat Idiot, to fill the early-afternoon slot (opposite Rush Limbaugh), as well as Public Enemy frontman Chuck D, actress Janeane Garofalo, and a small army of writers and producers who have SNL, the Daily Show, and Comedy Central on their résumés. Already they're delivering 17 hours of live talk five days a week in the nation's top media markets (albeit on low-rated stations). Plans call for blanket coverage coast to coast. "Our budgets are audacious," says Walsh, a tad breathlessly, his blue eyes beaming. "Our goals are vast."

And their confidence, to judge by Walsh's attitude, is limitless. Ask him for some sample material, and he recites one of 50 prerecorded travelogues, one for each state, that will pop up during broadcasts. "Gas up the Hummer and throw the hookers in the back seat!" Walsh demonstrates--too loud for this public place, but forgive him: This is one he recorded himself. "We're off to Nevada, the home of bling-bling!"

That sort of fare may or may not be enough to convince the country that Democrats--who, Walsh concedes, "are often accused of being boring, and we are!"--can rival Limbaugh and Bill O'Reilly. But you see where he's going with this: not so much smart radio--that would be NPR--as smart-aleck radio. "Funny in a way that makes you think and informs you so that you can fight back at the loudmouth right-wing zealot at the water cooler at work," says Walsh.

Walsh has a history of leading the pack. He was at HBO in the '80s and at AOL in the mid-1990s (both are now owned by the parent of FSB's publisher). Before all that he was a TV anchorman in West Virginia, and he still has the voice to prove it. Close your eyes, and you'll hear Bob Costas. Except Costas doesn't say "incredibly magnetic cat" (as Walsh does to describe his political hero, Hubert Humphrey), "super-cool cat" (that's Walsh on Kerry's deputy campaign manager, Marcus Jadotte), or "rational dude" (Walsh on himself).

Walsh served as an early Kerry consultant ("I was sort of the mini-Joe Trippi") and as an unpaid tech advisor to the Democratic National Committee. He earned the wherewithal to work for no pay (even now, he's content with $1 a year) during his run as CEO of fallen Internet highflier Verticalnet. Recently trading at $2 a share, Verticalnet peaked at a split-adjusted--and this is no typo--$1,388 in March 2000--the same year Walsh sold shares worth $44.8 million.

"This is not regime-change radio," Walsh insists. "If people think all we're about is trying to get George Bush out of office, we'll fail. We're trying to build a defensible, profitable, sustainable, high-growth media business." That means attracting a big crossover audience the way Limbaugh does. ("An extremely talented entertainer," Walsh concedes. "I envy him his numbers.")

Progress Media's business plan assumes losses of "meaningful amounts of money for a very meaningful amount of time"--at least two years. It's based on the assumption that mammoth signal beamers such as Clear Channel have rendered the old way of building a national radio audience obsolete. "A guy like Rush Limbaugh could start in a place like Fort Wayne, hit some numbers, circulate his tapes to other small station groups, and build the flame slowly," Walsh says. "Now two-thirds, maybe three-quarters, of the stations that matter are owned by two companies. There's no build anymore--you launch big." Dude!