WASHINGTON — Presidential politics veered into a congressional hearing on the economy yesterday as a top Republican lawmaker scolded New York’s senior senator for inviting two informal advisers to Senator Obama to testify before his committee.

The ranking Republican on the Joint Economic Committee, Rep. James Saxton of New Jersey, told Senator Schumer, the panel’s chairman, that it was a “shame” for him to politicize a hearing aimed at addressing the economic woes of America’s middle class.

Using his allotted time for questioning witnesses to berate Mr. Schumer, Mr. Saxton criticized Democratic lawmakers at the hearing for blaming the Bush administration for the nation’s economic slowdown. Mr. Schumer in particular had singled out the president while also linking the presumptive Republican nominee, Senator McCain, to the policies of the current administration.

Mr. Saxton noted that two of the four economists Mr. Schumer had called to testify, Elizabeth Warren of Harvard University and Jared Bernstein of the Economic Policy Institute, had advised Mr. Obama.

“That sets a really bad tone for the American people,” Mr. Saxton said, citing an article yesterday in Politico that noted the economists’ ties to Mr. Obama. “I think it’s just a shame that we’re here doing politics on the people’s money.”

The 13-term Republican, who is retiring from Congress this year, then suggested that the hearing be paid for by the Democratic Senatorial Campaign Committee, which Mr. Schumer chairs.

Mr. Schumer scoffed at the charge, telling Mr. Saxton he had no idea that Ms. Warren and Mr. Bernstein were advisers to the presumptive Democratic nominee.

“Who cares?” Mr. Schumer said. “I haven’t heard any of them mentioning anything political.”

He defended the hearing, which carried the wordy title: “How Much More Can American Families Be Squeezed by Stagnant Wages, Skyrocketing Household Costs, and Falling Home Prices?”

“This is not a political hearing. This is a substantive hearing,” Mr. Schumer said. He concluded: “You’re my good friend, Jimmy, but I don’t think you’re right on this.”

An aide to the Obama campaign confirmed that Ms. Warren and Mr. Bernstein served as informal advisers.

Republicans have made a habit of using Mr. Schumer’s leadership of his party’s Senate campaign arm to undermine his legislative efforts. When Mr. Schumer, who is the third-ranking Democrat in the Senate, led the charge against then-Attorney General Gonzales amid allegations of White House interference with the Justice Department, Republicans accused him of trumpeting the issue solely for political leverage heading into 2008.

Neither Ms. Warren nor Mr. Bernstein mentioned Mr. Obama or presidential politics during their testimony, which relied heavily on economic data. They painted a grim picture of the American economy, warning that declining wages and steadily rising prices for fuel and food were threatening the middle class.

“This is a critical moment in American history,” Ms. Warren, an economist at Harvard Law School, told lawmakers. “There has never been so many families, since the Great Depression, standing right on the edge.”

She cited data showing that because of a combination of increased costs and stagnant incomes, middle-class families had cut back on virtually all forms of discretionary spending, with the exception of alcohol purchases.

Both economists urged Congress to take action, with Ms. Warren stressing the need to address the credit crunch and Mr. Bernstein advocating a second stimulus package centered on aid to states and immediate spending on infrastructure projects.

Also testifying before the committee were Kristen Lewis of the American Human Development Project and David Kreutzer of the Heritage Foundation. Mr. Kreutzer offered the panel’s lone conservative voice and pushed for expanding offshore drilling to boost the domestic energy supply and reduce prices.