NEW YORK (CNNMoney) -- President Obama thoroughly denounced the budget plan favored by House Republicans on Tuesday, calling it "thinly veiled social Darwinism" that will only exacerbate income inequality in America.
The president's address, delivered to the American Society of Newspaper Editors, also marked the first time that he has called out Mitt Romney, his likely challenger, by name.
That passing reference, in which Obama linked the former governor of Massachusetts to the budget written by Rep. Paul Ryan and adopted by his House colleagues, marks an opening volley in a bitter campaign that will stretch until November.
"One of my potential opponents, Governor Romney, has said that he hoped a similar version of this plan from last year would be introduced on day one of his presidency," Obama said. "He said that he's very supportive of this new budget and he even called it marvelous, which is a word you don't often hear when it comes to describing a budget."
But Romney was not the main target on Tuesday. That distinction was reserved for Ryan, his budget and trickle-down economics.
"For much of the last century, we have been having the same argument with folks who keep peddling some version of trickle-down economics," Obama said. "They keep telling us that if we'd convert more of our investments in education and research and health care into tax cuts, especially for the wealthy, our economy will grow stronger."
Obama said the theory has failed, and that "the results of their experiment are there for all to see."
"In this country, broad based prosperity has never trickled down from the success of a wealthy few," Obama said. "It has always come from the success of a strong and growing middle class."
Conservatives would argue that Obama's description of "trickle-down economics" -- which is often called "supply side economics" -- is a simplification of their position.
And Ryan slammed Obama in a statement issued shortly after the president spoke.
"The president refuses to take responsibility for the economy and refuses to offer a credible plan to address the most predictable economic crisis in our history," Ryan said. "Instead, he has chosen tired and cynical political attacks as he focuses on his own re-election."
Obama went on to say that his guiding economic philosophy for the country -- described as a place where "everyone gets a fair shot and everyone does their fair share" in the pursuit of prosperity -- is superior.
Those themes of income inequality, which Obama said is "the defining issue of our time," largely echo ideas the president advanced during a speech in Kansas last fall and again at the State of the Union in January.
But this time, Obama used the contrast as a springboard to attack Ryan's budget plan, which he called a "Trojan horse disguised as a deficit reduction plan."
"It is really an attempt to impose a radical vision on our country," Obama said. "It is thinly veiled social Darwinism. It is antithetical to our entire history as a land of opportunity and upward mobility for everybody who is willing to work for it."
Obama criticized the Ryan budget for cutting too deeply into non-security discretionary spending, an area of the budget that funds education, research and development and most government agencies.
"You can be sure that with cuts this deep, there is no secret plan or formula that will be able to protect the investments we need to help our economy grow," Obama said.
Romney and Ryan, meanwhile, spent the morning in Wisconsin, where Republican voters will cast primary votes on Tuesday.
The attack from Obama, the substance of which had been reported Monday, sparked a rebuttal.
"So today, instead of standing up and saying, as the president, his [Obama's]policies have not worked, he of course will look for someone else to blame," Romney said. "This president is unwilling to take responsibility."
Obama had also scheduled high-profile events on primary days earlier this year, including a speech at a United Auto Workers conference on the day of the Michigan primary in February, and a news conference on Super Tuesday in early March.
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