MARION, Iowa - Mitt Romney tonight launched a fresh attack on President Obama, describing the commander-in-chief as "the great complainer."

"I want to see America united," said Romney at his third of four rallies in Iowa Monday. "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," said Romney. "I'm an optimist. I believe in the future of America. I'm not a pessimist."

While Romney criticizes Obama daily for his leadership and policies, today's attack was a change in rhetoric.

"I think President Obama wants to make us a European-style welfare state," said Romney. "Instead of being a merit society, we're an entitlement society, where government's role is to take from some to give to others. What I know is that if they do that, they'll substitute envy for ambition. And they'll poison the very spirit of America and keep us from being one nation under God."

President Obama's campaign press secretary, Ben LaBolt, had this response:

"While the President is fighting to build an economy that rewards hard work and responsibility, where everyone from Main Street to Wall Street plays by the same set of rules and everyone gets a fair shake, Mitt Romney has blamed middle class Americans struggling to make ends meet as 'entitled' and made clear he'd accept an economy where fewer people succeed no matter how hard they work. "