WASHINGTON -- Sitting outside a Starbucks Coffee shop in downtown Washington, D.C., Roger Stone, the famed GOP operative known for the dirty tricks he perfected as a Nixon aide, suffered a touch of nostalgia.

Across the street was 1701 Pennsylvania Avenue, an office building above a Caribou Coffee shop now known as a place for Obama administration aides to kibitz with lobbyists without recording it in the visitor's log. Forty years ago, it was the site of a different White House outfit.

"That was the site of the Committee for the Re-Election of the President," he declared, of the money-laundering entity behind the Watergate scandal.

Stone was a key cog in that piece of dubious political machinery, which encompassed two floors of the 1701 office building. He recalled going across the street to the Nixon White House in the morning for official business, only to come back in the afternoon with a bag full of cash in his hands.

Today, he remains in the cash-hauling game. But the enterprise is legal. Stone met with various news outlets on Tuesday to publicize a nascent effort he is running to help build a super PAC to support Gary Johnson, the former New Mexico governor who dropped his Republican primary bid to run as a libertarian candidate for president. Tonight, Stone is scheduled to meet actual moneymen. Decked out in a three-piece seersucker suit, with circular green-shaded sunglasses, he remains enthralled by the campaign game.

Johnson, he insists, has a real role to play in 2012, even if his prospects of actually winning the White House are basically nil. He will be on the ballot in either all 50 states or 49 out of 50 (they're working things out in Oklahoma, he says). And in several of the key battlegrounds, Stone believes that Johnson could pull in a percentage of the vote that could swing the balance.

Stone met Johnson at a Reason Magazine Christmas party two years ago, found him "an affable guy" and has been drawn to the former governor ever since, for ideological reasons. Their shared interests include opposition to the war in Afghanistan, a desire to balance the budget and for transparency at the Federal Reserve, as well as support for marriage equality and for marijuana legalization.

On Tuesday, it is that latter point that animates Stone the most, as he begins his pitch with a condemnation of the Obama administration for cracking down on medical marijuana growers. It is, he argues, "hypocritical" of a president "who was part of the Choom gang" now to demonize pot smokers. And herein lies the promise of a Johnson super PAC: All it would take is one billionaire who cares deeply about legalization to get a pro-Johnson entity off the ground.

Stone didn't offer a number for how much money he hopes to raise. He didn't even try to spin the prospect of Johnson pulling off an upset.

"This is a warm-up race," Stone said of 2012. "I have no allusions of him winning."

But he did make the case that in the Wild West, post-Citizens United world of campaign finance, a libertarian candidate could be an alluring investment for the right-minded, deep-pocketed donor. And with Rep. Ron Paul (R-Texas) effectively out of the race, the pieces are in place for Johnson to matter.

"I think a lot of Ron Paul voters will see that Gary Johnson is the only one who is going to continue the Ron Paul revolution," said Stone.