WASHINGTON — President Obama, drawing a contrast with what he called Republican trickle-down economics, called on Monday for temporarily extending the Bush-era tax cuts for people making less than $250,000 while letting the taxes of the wealthiest go up.


Leading Republicans promptly rejected that approach, saying that it would be a mistake to raise anyone's taxes when the economy was so weak.


Flanked by supporters handpicked to represent the taxpayers — 98 percent of households and 97 percent of small businesses, Mr. Obama asserted — who would benefit from his approach, Mr. Obama said only a strong middle class, not an ever wealthier top rung, would foster economic growth.


"These tax cuts for the wealthiest Americans are also the tax cuts that are least likely to promote growth," Mr. Obama said.


"We don't need more top down economics," he said. "We have tried that theory. We have seen what happened. We can't afford to go back to it."


Andrea Saul, the spokeswoman for Mitt Romney's presidential campaign, in a statement issued shortly before Mr. Obama spoke, said: "Unlike President Obama, Governor Romney understands that the last thing we need to do in this economy is to raise taxes on anyone."


House Republicans plan to vote this month to extend for a year all of the Bush tax cuts, for middle- and upper-income people alike. Mr. Obama countered with an immediate, one-year extension except for the wealthiest taxpayers in the highest brackets. Their taxes would go back up to the levels of the Clinton administration.


Conceding that the ultimate resolution of what has already been a long debate over extension of the Bush-era tax cuts "will be decided by the outcome of the next election," Mr. Obama said there was no reason to delay a temporary, partial extension.


Mr. Obama's proposal, an approach that he has been pushing through two years of fiscal debate, is not likely to break the deadlock in Washington over how to deal with budget deficits, an impasse that has only hardened as Republicans sense a chance to make gains in Congress this fall.


But by calling for an extension for just a year, Mr. Obama hopes to make Republicans look obstructionist and unreasonable. Trying to bounce back from another weak jobs report on Friday, he also hopes to deepen the contrast with his challenger, Mitt Romney. On Friday, the president said Mr. Romney would “give $5 trillion of new tax cuts on top of the Bush tax cuts, most of them going to the wealthiest Americans.”


From their stronghold in the House, Republicans plan to vote this week to repeal Mr. Obama’s health care law, hoping to energize their base even though they know that the campaign to abolish the law, which the Supreme Court upheld, stands no chance in the Democratic-led Senate. Republicans also renewed their call for an overhaul of the tax code.


“You know, what we ought to be doing is extend the current tax rates for another year with a hard requirement to get through comprehensive tax reform one more time,” the Senate minority leader, Mitch McConnell of Kentucky, said on Sunday on the CNN program “State of the Union.”


The struggle to frame the tax debate comes as the campaign moves into a period, only four months before the election, when the perceptions of voters begin to harden. Polls show a persistently tight race, with Mr. Romney closing in on Mr. Obama in certain swing states but with neither candidate able to break out decisively. Control of Congress is also up for grabs, with Mr. McConnell saying on Sunday that he believed the Republicans had a 50-50 chance to regain control of the Senate.


To find a compromise with Republicans on which Bush tax cuts to extend, Ms. Pelosi, the House minority leader, and Mr. Schumer, a member of the Senate Finance Committee, favor making $1 million the cutoff. Above that level, Mr. Schumer has said, people are not likely to spend the savings from lower taxes and help the economy.


Administration officials said they did not believe that the difference between the White House and these Democratic leaders was a big obstacle. They said that whether to use $250,000 or $1 million as a cutoff was more a matter of strategy than a “religious debate,” in the words of one official, who added that many other Democrats favored $250,000.