20 March 2012 Last updated at 07:11 ET

Article written by Mark Mardell North America editor

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Republicans stuck in the doldrums

 

Republican hopeful Mitt Romney campaigns in Illinois before the primary

Illinois has played a vital role in America's presidential history. In 1858 the all but unknown Lincoln made his name in a series of debates there with Stephen Douglas about slavery.

In 1968 there were riots outside the Democratic Convention as they debated who should replace LBJ who had dramatically given up the chance to fight for another term.

In 2008 Obama spoke to a crowd overwhelmed by emotion in Grant Park as he was elected.

I can always be proved wrong but I have got a feeling tonight is not going to be one of those nights.

Step back, and the Republican race is fascinating. What it says about the country and the Republican party is important.

But at the moment, the candidates are stuck like a ship in the doldrums, with not enough wind to move them forward. Or perhaps make that another area feared by sailors of old, the horse latitudes.

According to one theory at least they were called that because the ships would not move until some cargo, often horses, were thrown overboard. Until we hear the splash of "mute nostril agony" as one of the candidates hits the water maybe nothing will change.

Romney inches to victory

I have not spoken to one serious, objective observer who seriously doubts an eventual Romney victory.

It is indeed difficult to find flaws in the argument from Romney's campaign that the maths is with them if you trust caucus predictions. He inches towards the magic figure of 1144, which means he has won.

Rick Santorum hopes the Illinois primary will reverse his fall in the polls

Santorum mocks the maths and insists he will take this to the convention in August. He has a point. Victory by slide rule is not inspiring.

But even an Illinois victory would not be a game changer on its own. To alter the dynamic, Santorum would have to win everywhere, and win big.

An unbroken series of blow-out victories might just destabilise Romney and undermine the kids with the slide rules.

At the moment Rick Santorum is doing just enough to look like a serious candidate, but not enough to make anyone think he is going to win.

He inexplicably threw away any chance of making an impact in Puerto Rico by going out of his way to annoy Spanish speaking voters. He is now telling voters in Illinois that the election is not about the economy. He is falling behind in the latest polls.

Illinois may break the logjam. It is certainly possible. But I have the feeling that another result, and another 24 hours will just tell us there will be more hand-to-hand fighting before a victor emerges.