“The system we have now might work for the powerful and well-connected interests that have run Washington for far too long,” Obama said in his weekly radio and video address. “But I don’t. I work for the American people.”

He said the ambitious budget plan he presented Thursday will help millions of people, but only if Congress overcomes resistance from deep-pocket lobbies.

“I know these steps won’t sit well with the special interests and lobbyists who are invested in the old way of doing business, and I know they’re gearing up for a fight,” Obama said, using tough-guy language reminiscent of his predecessor, George W. Bush. “My message to them is this: So am I.”

The bring-it-on tone underscored Obama’s combative side as he prepares for a drawn-out battle over his tax and spending proposals. Sometimes he uses more conciliatory language and stresses the need for bipartisanship. Often he favours lofty, inspirational phrases.

On Saturday, he was a full-throated populist, casting himself as the people’s champion confronting special interest groups that care more about themselves and the wealthy than about the average American.

Some analysts say Obama’s proposals are almost radical. But he said all of them were included in his campaign promises. “It is the change the American people voted for in November,” he said.

Nonetheless, he said, well-financed interest groups will fight back furiously.

Insurance companies will dislike having “to bid competitively to continue offering Medicare coverage, but that’s how we’ll help preserve and protect Medicare and lower health care costs,” the president said. “I know that banks and big student lenders won’t like the idea that we’re ending their huge taxpayer subsidies, but that’s how we’ll save taxpayers nearly $50 billion (U.S.) and make college more affordable. I know that oil and gas companies won’t like us ending nearly $30 billion in tax breaks, but that’s how we’ll help fund a renewable energy economy.”

Passing the budget, even with a Democratic-controlled Congress, “won’t be easy,” Obama said. “Because it represents real and dramatic change, it also represents a threat to the status quo in Washington.”

Obama also promoted his economic proposals in a video message to a group meeting in Los Angeles on “the state of the black union.”

“We have done more in these past 30 days to bring about progressive change than we have in the past many years,” said the president in remarks the White House released in advance. “We are closing the gap between the nation we are and the nation we can be by implementing policies that will speed our recovery and build a foundation for lasting prosperity and opportunity.”

Congressional Republicans continued to bash Obama’s spending proposals and his projection of a $1.75 trillion deficit this year.

Almost every day brings another “multibillion-dollar government spending plan being proposed or even worse, passed,” said Sen. Richard Burr, who gave the Republican party’s weekly address.

He said Obama is pushing “the single largest increase in federal spending in the history of the United States, while driving the deficit to levels that were once thought impossible.”