“That’s surprising,” John Weaver, a political consultant and former John McCain adviser, told me this week. “I think especially with swing voters, they look at the auto industry and they see that government did work for them. It’s not just Wall Street that got help. It worked in a practical way in an industry that’s important to their state.” (Mr. Weaver isn’t working on the Romney campaign.)

I spoke this week with residents of both towns, and no one disputed that, from their perspective, the G.M. rescue has been a success.

“G.M. has been the catalyst for everything,” Wentzville’s mayor, Nick Guccione, told me. “They’ve already hired about 700 people, and they’re talking about bringing in over a thousand new jobs. And these are real jobs, with real wages. G.M. has brought in 1,300 construction workers for the new plant. We’re told that for every job they bring in, that creates five more jobs. It’s made Wentzville a more vibrant community. People can work, play, spend, shop.”

By many measures, Wentzville is thriving. In the two decades before 2010, the city’s population grew to 29,100, from 5,000, making it Missouri’s fastest-growing city, according to the city Web site. Mr. Guccione estimated that the current population was over 30,000 and said that per capita income and sales tax receipts had risen steadily despite the recession. A Sam’s Club will be the country’s largest when it opens in October, the mayor said. Voters approved a tax increase to pay for three new parks, and one of them, a large aquatic center, is scheduled to open next year.

Tony Thieman, owner of Thieman’s Carpet Company and a former president of the local Rotary and the Chamber of Commerce, said his business was up 18 percent this year. “I’m seeing an increase. It declined for three to four years, and now it’s improving. It’s not back to where it was, but I do see that happening in the next year or two.” He’s also a commercial landlord, with tenants that include a restaurant and a hair salon. “Their business is up. It’s a general positive swing,” he said.