Nowhere is today’s vote on a new UAW contract with General Motors being watched more closely than in Spring Hill, Tenn.  The new deal is expected to easily win approval from nearly 40,000 union autoworkers who began voting today.

The vote is expected to breathe new life into the Tennessee factory that built the Saturn until GM discontinued the money-losing car two years ago when the company teetered on the edge of failure.

Union officials say G.M. plans to build two mid-size cars at the plant, adding 600 jobs by next year and up to 1,700 jobs over the next four years.  That’s welcome news in a county where the plant’s closing decimated the local economy, driving its unemployment rate to 17 percent.  G.M. also plans to add jobs and production at factories in Michigan, Missouri and Indiana.

UAW President Bob King said the tentative agreement “creates thousands and thousands of new jobs … and brings production back to the United States that had been moved to Mexico and other parts of the world.”

The Tennessee plant’s reopening will add another benchmark in the comeback of the U.S. auto industry since the U.S. government bailed out G.M. and Chrysler.  It also reflects the new reality of lower pay and benefits for the union autoworkers who will build the new cars.  Although veteran G.M. workers will earn as much as $28 an hour, new hires are expected to make about $15 an hour, part of the new two-tier wage agreement that UAW members are voting on today.

The new contract would steady G.M.’s labor costs, analysts say, and allow it to stay profitable even if car sales remain historically low.

“It gives the company far more flexibility,” according to Rebecca Lindland, senior analyst for IHS Global Insight. “For the first time, the union’s fortunes are tied to G.M.’s performance, for better or for worse.”  The company earned $5.7 billion in the first half of 2011 after slimming down dramatically in the government-financed bankruptcy.

For some workers in Spring Hill, the factory reopening will end a painful period of commuting to other G.M. plants as far away as Michigan while their families stayed behind.  The mayor of Maury County, Tennessee, James L. Bailey, told ABCNews that the community is very excited about the new contract. “These manufacturing jobs that have been outsourced—it’s good for us to get those back in the United States, and I think it’s a strong psychological positive for everyone,” said Bailey.

Even more significantly, Lindland tells ABC News, “It means Americans are building things again. That’s incredibly important in this economy. ”