But members of Mr. Obama’s own party have backed many of the breaks. Senator Charles E. Schumer of New York was a leading proponent of the Nascar benefit, which helped a track in upstate New York; Senator Ron Wyden of Oregon helped push through the break for toy wooden arrow makers, which also benefited a manufacturer back home; and Mr. Kerry, who serves on the special Congressional committee that is trying to reduce the debt, has been a main driver behind the beer bill.

Republicans, who have taken a hard line against raising taxes, say that eliminating a tax break is the same as a tax increase, and they do not want to risk putting people out of work or slowing economic growth by ending benefits that they believe are helping certain industries get by.

This month, House Speaker John A. Boehner of Ohio said that “tax reform should include closing loopholes — not for purposes of bringing more money to the government, but because it’s the right thing to do.” But he did not offer any specifics, and he stressed that answers to the nation’s debt problems lie in cutting spending, not raising tax revenues.

“Tax increases destroy jobs,” he said.

Still, in the face of political pressure, Mr. Boehner and other Republican leaders have tempered their support, at least publicly, for some tax breaks that they once supported.

Mr. Boehner, along with fellow House leaders like Representative Eric Cantor of Virginia, Representative Kevin McCarthy of California and Mr. Ryan, who is the party’s leading crusader for spending cuts, were co-sponsors of a 2009 version of the beer tax break bill, which has never passed. Known as the Brewer’s Employment and Excise Relief, or BEER Act, it would halve the excise taxes on the first 60,000 barrels of beer for small brewers.

Steve Hindy, owner of Brooklyn Brewery, said his company stood to save about $400,000 a year if the tax break was approved.

“The tax break would boost our financial situation and allow us to further expand our business,” he said. “We would be able to create more jobs.”