Daring leadership can be dangerous to your political health. Just ask Pat McCrory, the energetic Republican mayor of Charlotte, N.C.

Seven years ago, McCrory convinced voters to approve a sales tax increase to finance an ambitious new regional transit system. The first light rail line is scheduled to open this autumn -- a big milestone for a Sunbelt town that's grown up, and sprawled far and wide, on private auto use.

But the late-November ribbon-cutting for the shiny new South Corridor line may be a dreary affair. Conservative activists have launched a referendum campaign to repeal the sales tax increase. The cutoff measure is on the Nov. 6 ballot and is believed to have a good chance of passing. McCrory's in some danger of losing his own re-election bid to a Democratic opponent that day; he might even be upset by an opponent in the Republican primary.

So what's this mayor's problem? The short answer: cost overruns. The original cost estimate for the South Corridor rail line was $227 million; the latest figure is $462 million. Why? Some mismanagement by contractors for the transit agency, which McCrory admits he should have discovered earlier. But mostly inflation -- especially ferocious nationwide run-ups in cement, metal and other construction costs.

Opponents had detested the idea of rail and the half-penny sales tax increase from the start; now, alleging gross mismanagement and waste of taxpayer dollars, they've found a golden opportunity to challenge it. A conservative Republican businessman put up significant cash to hire professional petition gatherers, who collected signatures in front of Wal-Marts and post offices.

McCrory complains of a pincer movement -- the right wing, fueled by talk-radio support, fighting the tax and claiming that Charlotte is too small for a light rail system, and skeptics on the left, ready to ax the tax because the first rail service isn't serving their part of the city.

So why did McCrory become his region's lead advocate for public transit at all? One reason was purely pragmatic. While the exciting idea of rail service got the most attention in the 1998 sales tax referendum, McCrory had another, bigger worry. The city had a dilapidated, poorly run bus system, supported by the city property tax. McCrory explains: "I thought a regionwide sales tax would be better -- people driving in from outside sharing the burden."
In fact, 65 percent of the proceeds from the expanded sales tax that opponents are attacking actually finances an expanded, successful new bus system. If the sales tax gets repealed, notes McCrory, "the entire bus system cost gets transferred back to Charlotte property taxpayers. I'm a conservative; I want to protect them."

Economically, the repeal would make zero sense. The city has wisely zoned and insisted on higher density, both business and residential, at the South Corridor stops; one result, say backers, is over $1 billion in new development, or redevelopment of blighted areas, along the line. The experience isn't unique. Just one example: About $8 billion in increased tax revenue and economic activity is claimed for Dallas' new 45-mile DART light rail system and its planned 48-mile extensions.

Indeed, while doubters nationwide carp about high rail system costs, evidence of big-time net benefits -- in property values, tax receipts and transportation alternatives in ever-more carbon-conscious times -- continues to roll in.

But why should an elected official take all the grief for pushing a new concept? Public transportation and land-use planning were nowhere on the agenda, McCrory acknowledges, when he ran in 1995. But a few weeks into office, he read a prior mayor's neglected "Committee of 100" report on public transportation. The report's thrust: The fast-growing Sunbelt city would choke on its expansion without quality bus and rail transit lines.

Then McCrory noticed for himself -- "When I took my nephews out on strollers, we couldn't get to the street because there were no damned sidewalks. We had no connectivity or pedestrian access -- just total reliance on the car." He began to see alternative futures: Charlotte could have tree-lined streets with bikeways and sidewalks, or "traffic lights every 15 feet, strip malls and unlimited pavement."

But could a Republican mayor sell public transit and its big upfront costs? McCrory took the Committee of 100 report to his mentor, retired Duke Power Chair Bill Lee, who was dying of heart disease. With analogy to his disease, Lee suggested: "You can wait until pain is great, but it's likely too late. Or you can act in anticipation. It will cost less, you'll have more chance for success. But it's a hard sell."

Says McCrory: "Some 12 years later, I never imagined how long and how hard the sell would be." When he announced the transit plan, "my own party thought I was nuts."

Indeed, the politics remain perilous. But why be mayor -- for indefinite terms, or for the legacy of a better city?

Neal Peirce's e-mail address is nrp@citistates.com.