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MARION, Iowa - During a grassroots rally while barnstorming across the nation's leadoff caucus state, frontrunner Mitt Romney made his most confident assertion to date in the Hawkeye state. "I need every single vote in this room and I need you to get another couple of other votes from your neighborhood and get them to caucus," Romney said, "We're going to win this thing with all of our passion and strength and do everything we can to get this campaign on the right track to go across the nation and to pick up other states and to get the ballots I need and the votes I need to become our nominee."Romney campaign aides immediately tried to walk back the candidate's comments, telling Fox News Romney meant he was going to win the nomination, not Iowa.

The slip-up is a departure for the rigidly on-message candidate, who has been extremely careful over the past week not to seem overly confident despite topping the latest polls here. And the comments could do exactly what the campaign has hoped to avoid -- making anything less than a first place finish in Iowa seem like major disappointment.

Mr Romney has dodged questions about predictions all week, saying at a press conference yesterday, "I'm pleased we're doing well. I cant tell you who's going to win this thing but I do believe that I'm going to have a great deal of support and that will give me the kind of boost I need as I go into a season of a number of other states."

It also might have the unintended consequence of distracting voters from his closing argument. Mr Romney and his campaign have carefully crafted a message over the past six months, talking about what they call President Obama's "failed Presidency."

Tonight was no different, with Romney offering some of his strongest criticisms of the President yet. "I've watched a president who's become the great divider, the great complainer, the great excuse-giver, the great blamer."

He went on to contrast himself by saying, "I want to have an America that comes together. I'm an optimist. I believe in the future of America. I'm not a pessimist."