Tom Smith is riding high on his combine these days, and not just because the seat is 12 feet from the ground.
Just weeks ago pundits and pollsters considered Pennsylvania's U.S. Senate race an easy win for incumbent Bob Casey, but new polls have some Democrats worried that it could slip into Mr. Smith's hands.
Polls still show Mr. Casey ahead, but his once substantial lead has been whittled to the single digits.
The freshman senator told reporters Thursday that he's been expecting the race to narrow as the election approached, pointing to the state's history of close contests and to the significant spending by his opponent.
"I'm actually not a bit surprised," he said during his appearance at a Communications Workers of America event in Hershey. "Way back in the spring, we began to prepare for this type of a race and I'm glad we did."
As the race has tightened, it also has gotten more national attention.
"This was always a seat that was considered safe for the Democrats so it hasn't been in the national calculation but now it could throw off all the seat counting that's going on. If this slips into the Republican column, that would turn the Senate calculus on its head," said Chris Borick, political scientist and polling director at Muhlenberg College.
Mr. Smith, 64, is a wealthy conservative farmer and businessman who made his fortune in coal, grain, trucking and car washes. Until now the only political office he has held was township supervisor, and that was decades ago.
Mr. Casey, 52, meanwhile, has been a state auditor general, state treasurer and, for the last six years, U.S. senator. He is chairman of the Joint Economic Commission and chairman of a Foreign Relations subcommittee.
But because he's been a mild-mannered, low-key lawmaker who doesn't seek the limelight, voters don't think a lot about him and that's given Mr. Smith's negative ads a chance to take hold, said political scientists and pollsters.
The Casey campaign responded by pointing out key roles the senator played in extending the payroll tax break and improving pay parity for women, but didn't have a counterattack at the ready, said Thomas Baldino, professor of political science at Wilkes University.
"When someone is running a negative campaign against you, you respond quickly with twice the force," he said. Bill Clinton was adept at that, he said.
"Casey was just too casual in how he approached the race and he miscalculated how much [money] Tom Smith would invest in this race," Mr. Baldino said. "Probably there was some expectation that he wouldn't need to spend much to defeat Smith."
When Mr. Casey has attacked back, his messages hammered home the same theme: that Mr. Smith is a radical tea partyer who would increase partisanship in already gridlocked Washington.
"That maybe stopped the bleeding a little bit, but I don't know how much you can keep going back to that. You've got to expand the message and do something more to define him," Mr. Borick said.
Mr. Casey had a lot of advantages going into the race. He's running in a blue state during a presidential election year, when voter turnout is higher, Mr. Borick said. He's also the son and namesake of a popular former governor.
"Those are a lot of structural advantages for Casey, but none of those are on their own a guarantee of success. For him to keep the lead means he's got to take this race seriously right until Election Day," Mr. Borick said.
Mr. Casey isn't used to tight general elections. In his last one he beat former Sen. Rick Santorum by 17 points -- the widest margin in any Senate race nationwide in 2006. It was also a wider margin than suggested by polls in the lead-up to that year's election.
"Casey always does well. He wins overwhelmingly," Mr. Borick said.
Mr. Smith, meanwhile, is working hard to chip away at the incumbent's lead in polls. The aim is to reach as many conservative Democrats as possible, said Smith campaign manager Jim Conroy.
"That's where we need to do well and those are the people we have to target," he said.
The plan has been as much about building up Mr. Smith as tearing down Mr. Casey.
"In addition to introducing Tom it's been our job to tell voters about Bob Casey's record. He wants to build himself up as an independent and a moderate, but his record doesn't support that," Mr. Conroy said.
That message is part of an aggressive statewide campaign that launched Mr. Smith from a political unknown to a contender.
"He built up is name recognition, and he's built it up so much that he's seen as a viable alternative to Casey," said political scientist Thomas Baldino of Wilkes University.
Mr. Smith was able to define himself, and Mr. Casey hasn't effectively challenged him on who he says he is, Mr. Baldino said. In the general election, Mr. Smith has portrayed himself as a moderate even though he was the most conservative of the five GOP primary candidates, Mr. Baldino said.
Republican presidential candidate Mitt Romney deserves some credit, too. As he's been rising in the polls, GOP candidates across the nation have been riding his coattails.
Still, with a voter registration advantage -- 4.3 million Democrats to 3.1 million Republicans -- many still expect Mr. Casey and President Barack Obama to win in Pennsylvania. Their challenge will be to get their supporters to the polls.
"Casey and Obama are in the same boat in Pennsylvania. If Obama carries Pennsylvania, Casey wins," he said.
Mr. Casey has unleashed a new burst of attack ads, and Mr. Smith says he has the cash to respond.
Campaign records show he's already put $16.8 million of his own money into the campaign and he's willing to spend more. How much more, he won't say. He responds to questions about it with a well-worn line: "How much? About half. The other half is Mrs. Smith's."
Including the Smiths' own money, the campaign has raised $19.6 million and still has $7.1 million on hand, according to the most recent campaign filings. Mr. Casey, meanwhile, raised just $9.2 million and has $5.2 million left.
Mr. Casey has been working to boost fundraising while Mr. Smith is logging miles on his campaign bus as he tries to let voters get to know him. His focus is on conservative Democrats that he knows he needs to attract to overcome the voter registration disadvantage. His campaign thinks he can do it if his message of fiscal constraint reaches his target audience.
A few months ago, hardly anyone outside Armstrong County had heard of him. Millions of dollars in advertising spending later, they know him now.
"You've got to build the name ID first and then you've got to win the race on the issues," said Smith campaign manager Jim Conroy. "We're doing that."
Mr. Smith has one liability that the incumbent doesn't: a challenger with the same name. Libertarian Rayburn Smith of Clarion County hasn't spent a cent, but he could be a spoiler in the race if confused voters cast ballots for the wrong Smith. In a race this close, an unknown Libertarian could siphon enough votes to tip the balance.
The pressure will be on Friday. That's when the candidates will square off at WPVI-Philadelphia in their only debate. Television viewers won't be able to see it until Sunday, though.
For a while it had looked like there would be no debate in the race, and that concerned the Pennsylvania League of Women Voters.
It's essential for voters to have a chance to hear from the candidates, said Bonita Hoke, the league's executive director.
"Whoever fills that spot is very important and should reflect the things that [Pennsylvanians] are concerned about," such as health care, climate change, Social Security, taxes and energy policy, said Bonita Hoke, executive director of the Pennsylvania League of Women Voters.
The candidates' positions couldn't be farther apart on those issues.
Abortion appears to be the only issue on which they've found a bit of common ground, but there's disagreement even there. Mr. Casey believes it should be allowed in cases of rape or incest while Mr. Smith is firmly opposed in all circumstances.
During his speech Thursday to a crowd of regional union workers, the senator drew distinctions on their approaches to Medicare, trade agreements and tax policy during his speech.
He emphasized his support of the payroll tax cuts and for a bill to make it harder for call-center jobs to be sent overseas, and his opposition to trade deals that he said would have hurt Pennsylvania jobs.
"We're confronted now as a state and as country is a very clear choice," Mr. Casey said. "Whether we're going to elect or re-elect people that try to find common ground, try to bring people together and try to focus on priorities like jobs instead of bringing an ideological, extreme and radical agenda not just to the campaign but to the work they would do in Washington."
Washington Bureau Chief Tracie Mauriello: firstname.lastname@example.org or 1-703-996-9292. Harrisburg Bureau Chief Laura Olson contributed from Hershey.