BLACKSBURG -- Another in a wave of political wildfires is sweeping through town.

Unlike past conflagrations sparked over where to put a school stadium or whether to extend a major road past a tony subdivision, the coming vote on an ordinance that would regulate the size of retail buildings could shape the town's topography and economy for decades to come.

Depending on who is speaking, the ordinance could protect struggling homegrown businesses and the small-town charm of Blacksburg. Or it could mean the death of the town's aspirations to build its retail tax base and stem the outflow of retail dollars to regional shopping centers in Christiansburg and Roanoke.

And it's a crucial, perhaps legacy-making, decision for the 1-year-old town council elected in the wake of a citizen revolution begun in 2004. Even longtime council watchers find it difficult to predict its vote margins on controversial issues.

The same is true of the coming vote on Ordinance 1450, which would require developers to apply for a council-approved special-use permit for any retail building larger than 80,000 square feet. Councilman Don Langrehr proposed it shortly after Fairmount Properties of Ohio submitted concept plans for a 40-acre redevelopment project along South Main Street that includes a big-box store widely thought to be a Wal-Mart Supercenter.

The council approved Fairmount's redevelopment concept including retail and residential buildings last year when it rezoned several acres of land to make way for it. But the newly added 186,000-square-foot big-box has caused a backlash. If passed, the ordinance could slow down or block the big-box. In response, Fairmount has filed a lawsuit asking the Montgomery County Circuit Court to protect the project from the ordinance. A hearing is scheduled for June 7.

The climbing pitch of the discussions has irritated some political moderates, including Councilman Paul Lancaster. "I'm real unhappy with both sides right now. I think the rhetoric has been turned up too high," he said.

He's unhappy that the ordinance has been fast-tracked, and the 80,000-square-foot limit seems arbitrary, Lancaster said. But the issue is so complex that "I don't want to fiddle with it now because people have enough trouble figuring out what it is," he said.

Mayor Ron Rordam, citing a pending lawsuit and the upcoming public hearing, said only that he is thinking about the wider implications of the ordinance. Councilwoman Mary Holliman has said she will vote for it, as has Langrehr.

Three council members -- Al Leighton, Susan Anderson and Tom Sherman -- did not respond this week to calls or e-mails seeking comment. But Leighton voiced support for the ordinance shortly after it was proposed. Anderson, based on previous comments, is expected to vote for it. Sherman has made no comment for or against the ordinance.

Supporters of 1450, including Blacksburg United for Responsible Growth, have said they are confident the ordinance will pass. Powerful groups, including the Downtown Merchants of Blacksburg and the political advocacy group Citizens First, also support it. A vote against the ordinance, some say, would be construed as a vote for a Wal-Mart or another big box, a potential career killer in town politics.

Dozens of supporters have stumped for the ordinance at public hearings before the planning commission and the council. They promise to show up May 29 as well. In fact, BURG has gone as far as to contact Fairmount's leasing agents to tell them about the mounting opposition.

"We're ... saddened that members of the Blacksburg community ... would try and undermine this overall development by attempting to inappropriately interfere with our business relationships," Fairmount principal Adam Fishman said this week. He added that the efforts have not harmed the development. But the proposed ordinance has "given our investment group pause. We're trying to determine what the right next thing is," Fishman said.

Economic development advocates worry that the ordinance, if passed, will undo years of work by the Blacksburg Partnership, the town's economic development arm, to draw the attentions of national retail chains. This local debate about the power of global chain stores to change a small town echoes other regulatory fights playing out across the country in fast-growing communities. A federal challenge to local ordinances such as Blacksburg's 1450 could be coming.

A handful of local and state courts have so far upheld the rights of localities to impose restrictions on retail size. But Brannon Denning, a law professor at Samford University in Alabama who studies retail size caps, says many of them may be vulnerable legally. The central questions are: Do such ordinances meddle in interstate commerce, a power reserved for the federal government? And do they inappropriately protect small businesses from large chain stores?

No such federal challenge has been initiated. But if big-box retailers and developers find themselves locked out of many communities, a challenge could be mounted, Denning said.