As you travel through the district's south, past vast cornfields, potato lorries, the Church of the Heartland and the Harvest Church, there is no doubt that this is deeply Republican territory. Mr Chocola won by huge margins here in 2004.
But the mood among many diehard Republicans has soured. There are local factors not helping Mr Chocola -- the new Republican governor, Mitch Daniels, a former White House budget chief, has infuriated Indiana voters by altering their time zones-- but two issues above all else are dragging the candidate down: an unpopular president and his war in Iraq.
"It's Iraq. It's the war," Ben Daulton said, during a lunch of meat loaf and pasta at a meeting of the Kiwanis Club in Rochester, a charity dominated by elderly Republicans. "I voted for Chocola and Bush. Now I don’t know. The Iraq policy is not succeeding. Without Iraq, Chocola would win hands down. If he loses, he can point to the war and the war alone."
At the lunch, and elsewhere in Rochester, everybody had the same view: Mr Chocola faced possible defeat because of Iraq. And Mr Bush's efforts to convince voters that Iraq was the central focus of the War on Terror appeared to be failing.
Roger Rose, a Republican county commissioner in Rochester, said: "Things are not going well in Iraq. Mistakes have been made. Chocola has drawn very heavily from President Bush in the past for support. He is now lagging in the opinion polls and the close association can do nothing but hurt Chocola."
A recent poll put support for Mr Bush in Indiana at only 37 per cent. Mr Chocola concedes that this will have an effect. "The President's approval ratings are lower than in the past. They influence every election around the country and I am not immune to that," he told The Times.
Mr Chocola's opponent is Joe Donnelly, a local businessman and moderate Democrat who lost in 2004 by nine points. Recent polls have him just ahead. "As I travel across the district, over and over again I hear a call for change," he said -- a soundbite echoing around America from nearly every Democratic candidate.
"Indiana is the key," Amy Walter, a non-partisan analyst, said. "It is literally the centre of the Universe right now."
