President Obama speaks about fiscal policy at George Washington University on April 13. (Mark Wilson/GETTY IMAGES)

It was billed as President Obama’s big speech on reducing the federal budget deficit. But the Wednesday afternoon address sounded at times like the speech he did not give when he launched his reelection campaign last week.

After months of carefully negotiating with congressional Republicans, often annoying his liberal base along the way, Obama repeatedly attacked the budget released by the House GOP last week in a sharp, partisan tone he has largely avoided since November’s elections.

In presenting his vision for reducing the budget deficit by $4 trillion over the next 12 years, he argued the difference between the Republican budget and his own vision was not just about policy but a larger philosophical gulf.

In the speech, he used as many words to attack the GOP proposal as to lay out his own.

“A 70 percent cut in clean energy, a 25 percent cut in education, a 30 percent cut in transportation, cuts in college Pell Grants that will grow to more than $1,000 per year,” Obama said. “That’s the proposal. These aren’t the kinds of cuts you make when you’re trying to get rid of some waste or find extra savings in the budget. These aren’t the kind of cuts that the fiscal commission proposed. These are the kinds of cuts that tell us we can’t afford the America that I believe in and, I think, you believe in.”

Without detailing his exact view of how he would change Medicare, he cast the GOP proposal to convert the program into one in which people get vouchers to buy insurance as a plan that would “end Medicare as we know it.”

“Their vision is less about reducing the deficit than it is about changing the basic social compact in America,” Obama said. He added: “There’s nothing serious about a plan that claims to reduce the deficit by spending a trillion dollars on tax cuts for millionaires and billionaires. And I don’t think there’s anything courageous about asking for sacrifice from those who can least afford it and don’t have any clout on Capitol Hill.”

The speech was a marked contrast to the “above the fray” approach Obama has taken in the past several months, particularly last week as he seemed to blame Democrats and Republicans equally for the near government shutdown. And it illustrated the major divide between the parties as they to seek to reform entitlements.

Obama not only attacked the GOP proposal but also noted that it was supported by “several of their party’s presidential candidates.” (Actually, most of the potential 2012 GOP candidates have offered measured remarks on the plan, praising the House Republicans for releasing it without declaring support.)

Even as he savaged the GOP proposal, Obama was less than specific about his own. He did not say exactly how he would reform how corporations are taxed, what he would do to achieve a simpler tax system or which defense programs he would cut. On Social Security, he not only didn’t announce a proposal but would not say whether one was likely to be included in the final legislation.

And Obama, who rarely personally interjected himself into the negotiations on the federal budget over the past two weeks, seems prepared to play a similar role on the deficit: He announced that a group of 16 members of Congress and Vice President Biden would negotiate over the legislation, allowing the president to remain out of the day-to-day politicking on the issue.

While attacking GOP ideas, Obama said he wanted to get a deficit reduction plan signed by June, which would be unusually fast considering Congress’s normal place in approving legislation.

But his speech seemed to offer limited room for compromise. He repeatedly called for increasing taxes for people who make more than $250,000 a year to help balance the budget, an idea strongly opposed by many congressional Republicans. He signaled strong opposition to how House Republicans would reform Medicare.

“I believe it paints a vision of our future that is deeply pessimistic,” he said of the GOP plan. “It’s a vision that says if our roads crumble and our bridges collapse, we can’t afford to fix them. If there are bright young Americans who have the drive and the will but not the money to go to college, we can’t afford to send them. ”