Ohio congressional Republicans say they will not completely back away from an anti-tax pledge they signed, but some are willing to raise tax revenue through capping or eliminating scores of deductions and credits that are available to wealthier taxpayers.

As President Barack Obama and Congress lurch toward an end-of-the-year deadline that could lead to more than $500 billion in higher taxes and federal budget cuts in 2013, a growing number of Republicans are grudgingly conceding that any compromise budget plan will include more tax revenue for the government.

By doing so, however, they risk breaking a pledge authored by Grover Norquist of Americans for Tax Reform and signed by Sen. Rob Portman and all 13 House Republicans from the state — including Reps. Mike Turner, R-Centerville, Steve Chabot, R-Cincinnati, Jim Jordan, R-Urbana. By signing the pledge, each lawmaker promised to “oppose any and all tax increases,’’ as well as opposing scrapping of tax deductions “unless matched dollar-for-dollar by further reducing tax rates.’’

But Republicans also wary of the alternative. By not compromising on a budget plan, the Republicans would be partly blamed for huge tax increases and spending cuts scheduled to go into effect on January 1.

Portman, House Speaker John Boehner, R-West Chester Twp., say they oppose raising individual income tax rates.

But Portman and Boehner have indicated they would support an overhaul of the tax code that would result in fewer deductions to the wealthy. In exchange, however, they insist that Democrats agree to spending restraints in the rapidly growing entitlement programs of Social Security, Medicare, and Medicaid.

Boehner yesterday said to “show we’re serious about reaching a bipartisan agreement, we have offered to accept some new revenues, provided the revenue comes from tax reform and is accompanied by significant spending cuts.’’

“Without spending cuts and entitlement reform, it is impossible to address our country’s debt crisis,’’ Boehner said. “We put revenue on the table. Now, it’s important for President Obama and congressional Democrats to tell the American people what spending cuts they’re willing to make.’’

Democrats, including Sen. Sherrod Brown, D-Ohio, have been resistant to tweaking Social Security, Medicaid and Medicare, with Brown signing a letter this week to Senate Majority Leader Harry Reid reiterating opposition to changing the program.

Others don’t leave much wiggle room.

Turner “does not support raising taxes in the middle of a recession, or for increased spending as the president has proposed,” said Tom Crosson, a Turner spokesman.

“Mr. Turner joined the House in passing legislation in August which would avert the cliff and not raise taxes on a single American,’’ Crossan said. “It’s unfortunate that the President has yet to articulate a plan which would provide a workable solution to this issue.”