Indeed, rural and small-town voters are most apt to be deeply conservative —37 percent describe themselves that way compared to 33 percent in the suburbs and 31 percent among urban voters, according to surveys in 16 states where exit or entrance polls have been conducted. What's more, 68 percent of rural voters identified themselves as born again or evangelical Christians, compared with about half in urban or suburban precincts.
In the states that will vote in the next two weeks, Wisconsin has the highest concentration of rural small-town voters at 41 percent, according to the 2008 GOP primary exit poll. The state this year is considered a toss-up.
Santorum looks strong in Louisiana, where social conservative Mike Huckabee won in 2008 over John McCain, the eventual Republican nominee. Huckabee won 43 percent of the vote, aided by sizable majorities in the rural and predominantly Protestant northern part of the state.
But the rural-urban, Santorum-Romney divide also raises questions about how strong Santorum would be against Obama should he succeed in his long-shot quest to deny Romney the nomination.
The suburbs are strongholds of swing voters that have been crucial in presidential elections for years.
"He struggles in the swing areas of swing states," Kevin Madden, a consultant for Romney, said of Santorum. "That would put us in a difficult position to win back the presidency. I don't think there is much confidence that he would all of a sudden find the message in a general election."
Santorum, however, sees a model in the conservative candidates who succeeded in the 2010 general election by focusing their campaigns on limited government.
"Whether you are a conservative or an independent or a moderate, I think people are very concerned about the scale and size of the government and this intrusion into people's lives," he said, answering questions outside a fish processing plant in Kenner, La., this week. "We can make this campaign about that."
Santorum appeals on several levels. His social conservatism and religious underpinnings attract some while others like his small-government message.
"His Christian values — it is one of the things that stands out about him," Larry Glascock Jr., a West Monroe, La., truck driver, said at Santorum's stop Friday. "The country needs to turn back to God."
Others like his desire for a smaller government.
"I don't want any big government, no mandates," said James B. Terral, a retired accountant from West Monroe. "Personally I think an employer should not be forced to do anything but pay an employee. They don't need to baby sit them and they don't need to act like they own them. We need more freedom to do what you want to do."
AP Deputy Director of Polling Jennifer Agiesta in Washington contributed to this report.
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