Warning against what he said would be severe cuts to college scholarships, medical research, national parks, and even technology to make accurate weather forecasts, Mr. Obama said the Republican budget was “so far to the right, it makes the Contract With America” — Newt Gingrich’s legislative manifesto of 1994 — “look like the New Deal.”  Mr. Obama’s scathing attack, in a speech to editors and reporters from The Associated Press, was part of a broad indictment of the Republican Party that included the president’s likely opponent in the fall, Mitt Romney.  The House budget, and the philosophy it represents, Mr. Obama said, is “antithetical to our entire history as a land of opportunity and upward mobility for everyone who’s willing to work for it — a place where prosperity doesn’t trickle down from the top, but grows outward from the heart of the middle class.”  Republicans fired back quickly at the president, with the House speaker, John A. Boehner, accusing him of lobbing “partisan potshots” at Republicans rather than responding to their budget plan with a responsible counteroffer. A spokesman for the House Budget Committee, Conor Sweeney, said Mr. Obama’s assertions about the cuts in the budget “are simply false.”  For Mr. Obama, it was the latest in a string of combative speeches, in which he has sought to make House Republicans a proxy for the Republican Party and cast himself as a brake on their radical agenda.  “I can’t remember a moment when the choice between competing visions of our future has been so unambiguously clear,” Mr. Obama said.  Americans, he said, cannot afford to elect a Republican president at a time of fragile economic recovery, with a weak job market and a crushing debt from “two wars, two massive tax cuts and an unprecedented financial crisis.” The widening gulf between the rich and everyone else, Mr. Obama said, was hobbling the country’s economic growth. He cited studies that found that societies with less income inequality had stronger and steadier growth.  “In this country, broad-based prosperity has never trickled down from the success of a wealthy few,” the president said. “It has always come from the success of a strong and growing middle class. That’s how a generation who went to college on the G.I. Bill, including my grandfather, helped build the most prosperous economy the world has ever known.”  Mr. Obama’s themes echoed his State of the Union address in January and his speech in Osawatomie, Kan., in December, when he invoked a Republican president, Theodore Roosevelt, who he said combined a fervent belief in the free market with a resolve to protect those vulnerable to its excesses.  But the president turned a harsh new spotlight on the 2013 budget, drafted by Representative Paul D. Ryan, a Wisconsin Republican who chairs the Budget Committee. The proposal, he said, calls for across-the-board cuts in discretionary spending, as well as tax cuts, which he said would disproportionately benefit households earning more than $250,000 and would cost $4.6 trillion over the next decade.  “Disguised as deficit reduction plans, it is really an attempt to impose a radical vision on our country. It is thinly veiled social Darwinism,” Mr. Obama said. “And by gutting the very things we need to grow an economy that’s built to last — education and training, research and development, our infrastructure — it’s a prescription for decline.”  Singling out Medicare, the president asserted that the Republican plan to shift people to a system of vouchers would drive up the cost of health care for the elderly, since private insurance companies would target the youngest and healthiest people and leave the rest to rely on Medicare.  For millionaires, the president said, the average annual benefit of the tax cuts would be $150,000 — money that he said could be used to pay for computer labs in schools, salaries for police officers and firefighters, medical care for veterans and a year’s worth of prescription drugs for older people.  The White House’s calculation for the tax benefit is straightforward, but Republicans on the House Budget Committee say it is wrong. The average household earning more than $1 million would gain $46,000 from the House budget’s repeal of the Medicare hospital insurance tax that was part of the health care law, the Republicans said, and $105,000 from the extension of the Bush-era tax cuts that Mr. Obama wants to see expire next year.  But the shape of the tax code is left largely unknown by the budget. The blueprint calls for the six existing income tax rates collapsed into just two, 25 percent and 10 percent. The revenue loss would have to be made up by the repeal of unspecified tax credits and deductions. It would be up to the House Ways and Means Committee to determine how that would be done.  In theory, tax writers could focus on tax breaks that primarily help the rich, like the deduction for charitable giving, or end the biggest tax breaks only for upper income earners. But Democrats say such selective changes to the tax code would never recoup such large cuts to income tax rates.
With Republicans starting to coalesce around Mitt Romney as the partyâs likely nominee, Mr. Obama was sharpening his political message for the election.