SPRINGFIELD - Whenever he has half an hour free, Joe goes into the yard of his little house to split logs. "It's fun for me. It's the only thing that really gets my mind off the election." In the living room there is a pool table, a bearskin on the wall, and his tools. "I still work as a plumber and a carpenter. A man has a physical need to build something, every day."

Yes, the man who has opened the door for us, standing there barefoot, is him: Samuel Wurzelbacher, otherwise known as "Joe the Plumber." While Obama was passing through his neighborhood four years ago, Joe had asked him why taxes on small businesses were so high. "When you spread the wealth around, it's good for everybody," Obama replied.

Their filmed conversation was posted on the Internet, and "Joe the Plumber" became a celebrity, used every which way by John McCain to try to turn the tide of his faltering campaign.

Four years later, Joe is a candidate for the House of Representatives for the ninth district of northern Ohio, a slice of America that may decide the presidential election. No Republican has ever won the White House without winning this territory, and Romney knows it. The two candidates have spent $9 million on television spots within the past week in Ohio, more than in any other state.

Whenever Obama has time, he hurries back to Ohio, and analysts say he is counting on the tiny lead that polls are still giving him here, now that other key states, like Florida, seem to have swung toward the Republicans.

The president's campaign has 125 offices in Ohio, many of which have stayed open since 2008 to continue to register potential voters. The result is that in early voting data, which tallies votes sent in by mail before the official ballot on November 6th, Democrats hold a solid lead on Republicans. Obama hopes to do well here partly because unemployment in Ohio is at 7%, almost one point below the national average, and there is a large female electorate. The Republicans insist that the state's good results are thanks to GOP Governor Kasich.

In this tense election atmosphere, Joe's campaign is highly significant. His district is in the region of Ohio that counts the highest number of factories, whose blue-collar union workers tend to favor Democrats. His opponent is Marcy Kaptur, in office since 1983, who trounced Dennis Kucinich, ex-mayor of Cleveland and former presidential candidate, in the Democratic primary earlier this year.

Joe lives about seven miles from the Toledo Chrysler factory, the biggest in the state. The company has invested $500 million in the plant, promising to hire 1100 workers to build the new Jeep. Obama has visited the factory to declare his commitment to the renaissance of the auto industry, adding that Romney wanted to let it die. In this part of the country, one job in eight depends on the automobile.

Joe knows he has an almost impossible task. "Marcy Kaptur talks a lot about Detroit being saved, and I understand why. It's an advantage for her," Wurzelbacher says. "But I have another argument: What brought the auto industry to the brink of bankruptcy? Excessive taxation, too many government regulations, and the government's idea that it should tell businesses how to manage their own affairs."

Having learned his trade during his years in the Air Force, Wurzelbacher combines his small government program with a robust program to help the nation's veterans. "But I don't trust the media," he adds. "They always twist my words. So I have to go out and shake hands, and hope that every voter I get will convince ten more to support me."

North-South divide

The GOP, however, does not believe their favorite plumber can actually win: in fact, Romney has not embraced him as McCain did. But the Republican presidential nominee is playing for big stakes in this part of Ohio. In the southern part of the state, Romney is certain to have the support of the Tea Party, and other evangelical Protestant conservatives from rural areas.

In the northern manufacturing regions he has to draw enough independent voters away from Obama to change the equation. In 2008 Obama took Ohio from McCain. Ohio senator Rob Portman, who prepared Romney for the debates, says that this is possible. "Romney could win even without Ohio, but we don't recommend that he run that risk. Our polls show that the candidates are neck-to-neck. We have to persuade enough middle-class and blue-collar voters that we are the real solution for the crisis."

One of these voters is Chuck, a truck driver who lives across the street from Joe in a little house already decorated with pumpkins, witches and ghosts for Halloween. "I'm a Republican, but I haven't made up my mind yet. There is so much at stake, and I don't know which candidate can really make the economy start up again. I'm going to talk to Joe to see if he can convince me."

It is possible that Joe will lose anyway, though, and go back to being a plumber. But in the meantime, he may once again hold the power to change the handful of votes that could decide the race for the White House.