The campaign for the regional transportation tax has downtown Atlanta offices, paid staff and $8 million.

The campaign against it has volunteers, dinner meetings, rifts --- and grass-roots passion.

A July 31 referendum for a 10-county, 1 percent sales tax for transportation projects may be the most important issue facing the region in a generation, and it has drawn fervid opposition. Over 10 years, it could yield $7 billion worth of transportation infrastructure, and the $8 million, privately funded campaign for it might be the biggest war chest in the history of such measures.

And opponents mean to stop it.

Skeptics from opposite ends of the political spectrum have expressed misgivings --- too much mass transit on the referendum's projects list, or not enough --- and some have outright said they will oppose it. The angry emails have flown for months. Now fragmented groups are trying to organize into a serious operation, reaching out for allies, forming committees to get the vote out, and setting up websites and even a political action committee.

"It's just like David and Goliath, I tell you that, " said John Evans, president of the NAACP DeKalb County branch, which opposes the referendum as weak on transit. The anti-tax organizers don't know how much strength they can tap, he concedes. "But we're going to find out."

The real question is where the mass of voters will come down.

A poll conducted by The Atlanta Journal-Constitution last year found most people weren't familiar with the referendum, but that it had razor-thin support. It also found weak points such as lack of trust, points the opposition means to press.

A variety of voices

Groups of tea party supporters from Cherokee County to Fayette County have added the referendum to their anti-tax agendas; others have made it a signature cause.

From the other side of the political fence, a handful of local leaders in south DeKalb County have come out against the referendum, too. They say that low-income voters who paid the MARTA tax in Fulton and DeKalb counties deserved more transit, specifically a rail line along eastern I-20. Instead, they got less: $225 million for express bus service there. There are also hundreds of millions of dollars for MARTA on the project list.

Jeff DiSantis, a Democratic political consultant, said the south DeKalb opposition was "potentially problematic" for the referendum, because that's an area where it would expect to have a base of support.

There's no monolith.

Anti-referendum leaders have popped up and dropped out, and the Georgia Tea Party just ousted some board members, partially over their activism. Transit advocates are torn over whether something is better than nothing.

Two weeks ago, one group set out to organize a coordinated, grass-roots campaign.

In a corner of a northern Marietta steakhouse, three dozen activists, many also adherents of the Georgia Tea Party but not speaking for that group, got down to business.

It wasn't slick. The representative on messaging had no update. The head of opposition research had "just really been looking" at newspapers and collecting emails. Leaders couldn't get anyone new to volunteer to keep track of referendum events. But they were brimming with ideas, which they traded for hours.

Many attendees wore red anti-referendum stickers, and one held an "Ax the Tax" sign pasted over from a previous campaign against the special purpose local option sales tax, or SPLOST. They have a website, traffictruth.net. (Other opponents have set up sites, including notsplost.org, tsplost.info and tsplost.wordpress.com.) They plan to go to public events such as parades to get the word out.

"They've got $8 million on their side, but we've got the truth on our side, " said Field Searcy, who led the meeting.

The pro-tax campaign had its stumbles, too, losing its lead strategist and its communications director last year.

Though Searcy pleaded that his group is "nascent, " Searcy believes its mission is more important than meets the eye. He fears that a U.N. agenda on changing traditional suburban development patterns is related to the Atlanta referendum.

"We're very concerned about loss of freedom, " he said. "This whole transportation issue is about regionalism."

Strange bedfellows

The opposition has brought together odd allies.

The DeKalb NAACP branch contends the referendum's treatment of Fulton and DeKalb taxpayers and commuters is "racist"; they say the project list underserves African-American commuters.

The Cobb County meeting was nearly all white, and attendees' concerns go in the opposite direction. With 52 percent of the regional list's money going to buses and trains, most tea partyers think that's already too much.

But until July 31, the two sides are bedfellows.

"You have no permanent friends and no permanent enemies, " said Larry Johnson, a south DeKalb County commissioner who opposes the referendum. "Just permanent interests."

Ashley Robbins, president of Citizens for Progressive Transit, a public transportation advocacy group, agrees with Johnson that an I-20 rail line should be built. But she supports this referendum. "Is the south Dekalb project fully funded?" she asked. "No. But DeKalb had two large-ticket items, the Clifton corridor [to Emory University] was the more shovel-ready project, and it serves more area with more employment centers."

Voters may or may not agree. First, they want more facts.

Chad Belinfanti is vice president of a neighbors' association in the I-20 corridor, and "wholeheartedly" agrees there should have been a rail line there. But he appreciates that there's at least $225 million for express bus service there. Mostly, he wants to know more about the project list.

"I wouldn't say it would sway my vote against it, " he said. "I think I'm in the category with, 'Not enough information.' "

Some of the most powerful anti-tax arguments come from Bob Ross, a founder of the Fayette County Issues Tea Party. He produced a devastating photo of a river of cars on an Atlanta highway, showing what he claims would be the minimal congestion relief bought by the 10-year tax.

Ross and others concede the tax legally cannot run past 10 years unless voters renew it; but if not, they ask, where will the extra money come from to operate all those new projects after the 10-year tax expires?

In addition, they are furious that the "privately funded" referendum campaign includes money donated by self-taxing business districts, such as the Cumberland Community Improvement District.

Cumberland CID Chairman Tad Leithead said that the money is going to the "education" side of the campaign, not "advocacy, " and that is legal.

Finally, opponents argue the tax is illegal, because the state constitution does not give regions the power to tax an unwilling county. Advocates say it passes legal muster.

Whatever works will be fine with Frances Wagner, a retired teacher who attended the Marietta after-dinner meeting. But she knows it won't be easy.

"Not one person at my subdivision had one earthly idea about what's going on, " she said. "This is what makes it an uphill battle."