Mitt Romney looks set to win in Tuesday's primary in Illinois, according to a Public Policy Polling report out on Monday morning.

The poll shows Romney leading Rick Santorum 45 percent to 30 percent. Newt Gingrich trails at 12 percent and Ron Paul holds about 10 percent.

Part of the reason for Romney's lead could be the level of support by rural voters in Illinois, with whom he has a small lead over Santorum even though the former Pennyslvania senator tends to do better among those voters nationally.

Romney is leading by stronger margins among voters who live in urban areas, 46 percent to 23 percent over Santorum, and those in the suburbs, 50 percent to 29 percent.

The poll holds more bad news for Santorum. Public Policy Polling found that he led among his bread and butter supporters -- evangelicals, Tea Partiers and those who describe themselves as "very conservative" -- by lower margins than he has recently. His favorability also was at a lower percentage, 55, than it has been recently, according to the poll.

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