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Romney: 'We're going to win this thing'

MARION, Iowa -- Speaking before a crowd of at least 500 supporters here in a suburb of Cedar Rapids, Mitt Romney unleashed a torrent of cheers at the end of his rally when he appeared for the first time to predict a flat-out victory in tomorrow's Iowa caucuses.

Almost half of the Iowa voters polled last week say they still aren't sure who they'll vote for on Tuesday night. Voters say they are not sure who has the best chance to beat President Obama. NBC's Ron Mott has more.

"You guys, I need you tomorrow night," Romney said. "I need every single vote in this room, and I need you to get a couple of other votes from yours in your neighborhood and get to your caucus. I need a great showing in Cedar Rapids. 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. That’s what we’re going to get."

The proclamation marked a shift for Romney, who's campaign has sought to tamp down expectations after a series of polls returned Romney to the frontrunner's perch here last week. After the rally, a Romney spokesperson told reporters that the former Massachusetts governor was saying he would win the nomination, not predicting a caucus victory.

The candidate himself had also been striking a more cautious tone regarding an Iowa victory, telling reporters and well-wishers in interviews and on rope lines that he thought he would do well on caucus night, but would make no predictions.

Republican presidential frontrunner Mitt Romney tells TODAY's Savannah Guthrie he thinks he'll do well in Iowa but says he's "not predicting a win" in the state's caucuses. 

"I'm pleased we're doing well. I can't 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," Romney told reporters at a press conference yesterday afternoon.

Today, Romney has seen a series of progressively larger and more enthusiastic crowds at each of his first three campaign stops, and at each stop he kept his focus squarely on President Obama. At the third rally in Marion, he delivered his most direct assault on the president yet today, unveiling a laundry list of new labels for the president, which was also met by cheers.

"I want to see America united," Romney said. "I've watched a president who's become the great divider, the great complainer, the great excuse-giver, the great blamer. 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."