we re only a day away from a crucial primary that could determine where this republican marathon is headed. fresh off a run away win in puerto rico, mitt romney is now looking to score big in illinois. rick santorum needs a strong showing as he tries to deny romney the nomination. the two rivals have long since taken off the gloves, but now they have put on some brass knuckles as well. our national correspondent jim accosta is in chicago with the very latest. the top two gop contenders are practicing their own brand of chicago style politics on this day before the illinois primary and both rick santorum and mitt romney are proving to be untouchable. reporter: the battle for the gop nomination has come to illinois and in the land of lincoln the republican party is a house divided in an uncivil war of words. i m somewhat experienced in the economy, i m not an economic light weight. president obama is. we re not going to be successful replacing an economic light weight wit