Reporting from Charlottesville, Va. — Republican Robert Hurt had barely begun his opening statement in the congressional candidates' debate here last week when he accused his Democratic opponent of endorsing "job-killing cap and trade."
Hurt, a state senator, repeated the charge five times in the next hour, insisting each time that incumbent Rep. Tom Perriello's vote last year for a House energy and climate change bill would cost the state 50,000 jobs if it becomes law.
True or not — Perriello didn't respond — the charges have potency far beyond this fiercely contested swath of central and southern Virginia. In much of the nation, "cap and trade" has become a dirty phrase this election season, and the political storm over global warming's causes and solutions may determine several key races.
For the first time in nearly a decade, not one Republican running for the Senate supports proposals to limit carbon emissions and trade pollution rights. Most openly question the science of global warming or denounce it as a hoax.
In some races, especially in coal-producing, farm and factory states in the mid-Atlantic and Midwest, partisan rivals appear united in their condemnation of major climate change legislation.
At an Oct. 18 debate in Morgantown, W.Va., the Democratic nominee for Senate, Gov. Joe Manchin III, said President Obama was "dead wrong on cap and trade," and that it would ruin the economy. His Republican opponent, John Raese, called global warming a myth.
Even Sen. John McCain (R-Ariz.), who introduced the first Senate cap-and-trade bill in 2003 and vowed during his 2008 presidential run to make it a priority if elected, has joined the skeptics' ranks. "I think it's an inexact science," he told a voters forum in New Hampshire.
The issue is on the ballot only in California. Carly Fiorina, the GOP's Senate nominee, favors Proposition 23, which would suspend the nation's stiffest global warming restrictions. The incumbent, Democratic Sen. Barbara Boxer, wants to keep the law.
Polls suggest several House races may turn on whether the incumbent voted for the cap-and-trade bill that narrowly passed the chamber in June 2009. A similar measure stalled in the Senate amid intense bickering and appears doomed for the foreseeable future.
Heather Taylor-Miesle, director of Natural Resources Defense Council Action Fund, which supports climate change legislation, said her group's polling of 23 battleground districts indicated voters were more likely to back Democratic lawmakers who voted for the bill and stood by it.
"With so many races so close, it could have a significant effect on the outcome of the election," she said.
But Jon McHenry, a Republican pollster who has surveyed 31 House races around the country for the American Action Forum, a conservative-leaning policy institute, said his data indicated the opposite.
"I'd be surprised if there are any Republicans willing to say they support cap and trade now," he said. "Where a Democrat is in a competitive race, it's a clear advantage for the Republicans to campaign against it."
Advocates say a market-based system would help create "green" jobs, spur investment in alternative energy sources and reduce reliance on foreign oil. Opponents argue it would stunt the economy, raise energy costs and do little to cool the climate.
For now, the battle over climate change appears to have put Democrats on the defensive.
In North Dakota, an energy-producing state, Rep. Earl Pomeroy has been forced to explain why Democrats held a vote on the cap-and-trade bill at all, even as he has made clear his opposition to the legislation.
Speaking to a coal industry group this month, Pomeroy, a moderate Democrat first elected in 1992, said the vote was Nancy Pelosi's "biggest mistake as speaker — and she's made a lot of them."
In coal-rich southwestern Virginia, Democratic Rep. Rick Boucher, who has served 28 years in the House, has been pounded for his vote on global warming. Boucher sits on the House Energy And Commerce Committee, where the bill originated.
"If you can point to one reason that Rich Boucher is in trouble, it's the cap-and-trade vote," said Isaac Wood, who studies House races at the University of Virginia Center for Politics. "People say he's demonizing coal and threatening their jobs."
Boucher said he helped negotiate provisions "to get the best deal for coal" he could in the legislation. The final bill included tens of millions of dollars for "clean coal" technology, funds that would have directly benefited the region.
"I've had to explain it," Boucher said in an interview. "It's not easy to explain. It does not translate very well into a 30-second commercial."
In the adjoining district, Perriello has tried to turn the argument to one about clean energy and jobs. Trailing in the polls all year, the freshman Democrat has trumpeted his efforts to funnel federal funds to renewable energy projects in the economically depressed region.
"This is a good issue for us," Perriello said in an interview outside a Charlottesville school.
"I think my message of energy independence and green jobs still beats the Republican message of burying your head in the sand and doing nothing, even in a very conservative district," he added. "People understand that this needs to happen."
But even some of his supporters are skeptical.
Roy VanDerHyde, who runs a dairy in Chatham, received about $1.2 million in state and federal grants this year to harness methane gas produced from cow manure. In another month, he said, his herd will provide enough electricity to power as much as 600 homes.
"I'm split on cap and trade," VanDerHyde said. "If it works, it could make my [project] a gold mine. But it will cost so much to run the dairy, it will be a wash. That's what I'm worried about."
James Oliphant of the Washington bureau contributed to this report from Bismarck, N.D.