Illinois gets its turn tomorrow on the GOP merry-go-round, in a rare meaningful primary for the state.  Only Mitt Romney and Rick Santorum have seriously campaigned in the Land of Lincoln, but a new PPP poll shows that it may wind up being a one-man race:

Mitt Romney is headed for a blowout victory in Illinois on Tuesday. He leads with 45% to 30% for Rick Santorum, 12% for Newt Gingrich, and 10% for Ron Paul.

Romney’s particularly strong among voters who live in suburban areas (50-29) and with those who live in urban areas (46-23). But he’s even running slightly ahead of Santorum, 38-36, with folks who identify as living in rural parts and that strength with a group of voters he hasn’t tended to do that well with is why he’s looking at such a lopsided margin of victory.

Romney tends to win moderates in most states and Santorum usually win voters describing themselves as ‘very conservative.’ The swing group in the Republican electorate is those identifying as just ‘somewhat conservative.’ Romney is winning those folks by a whooping 60-20 margin in Illinois. Romney’s also benefiting from a 52-28 advantage with seniors.

More than a quarter of voters polled over the weekend say they could still change their minds (28%), so there is some possibility of a surprise.  Santorum has outperformed the polls in Alabama and Mississippi, and could be lurking for a surprise victory in Illinois, too.  However, if PPP’s numbers hold up, there isn’t much in the poll that would show late-deciding voters to break his way.  Favorability numbers are almost a wash, with Romney at 57/34 and Santorum at 55/36, for instance.  Slightly more voters identify as “somewhat conservative” (39%) than “very conservative (35%), and only 36% of voters are evangelical Christians.

Of course, this is also a pollster that self-identifies as a Democratic Party polling firm, and that’s evident from some of the stupid questions asked later in this survey.  Among them are such narrative-builders as Do you think that interracial marriage should be legal or illegal?, Do you believe in evolution, or not?, and Do you think Barack Obama is a Christian or a Muslim, or are you not sure?  I first noticed these questions from PPP in its Southern-state polling, but they apparently want to make a national case for ridiculing Republican voters.  Feel free to judge credibility on that basis.

Back on topic, Romney’s team rolled out an ad today showing their biggest endorsement yet … even though it’s from 2008:

Santorum has already explained this as his choice of the most conservative candidate in that cycle. I agree with him; I caucused for Romney in 2008 for the same reason, and I will caucus for Santorum on Saturday on that basis in this cycle. Still, it’s a clever point that Romney is making, and it will be an object lesson to politicians with ambitions for higher office about the risks of endorsements.