Continued from page 1

Some Democratic lawmakers argued Tuesday that the government can’t raise enough revenue without raising marginal rates. Mr. Durbin told reporters that changes to the tax code alone would affect too many middle-class taxpayers.

“I think you’ve got to include [an] increase in rate, as well as changes in the code itself,” Mr. Durbin said. “If you are going to go to the tax code and hit deductions and credits to get to your number, you are going to get right in the middle of working families and middle-income families, and I don’t think Democrats will stand for it.”

Sen. Ben Cardin, Maryland Democrat, said the best way to raise reliable revenue in the fiscal-cliff negotiations would be by raising taxes on the nation’s top earners and also increasing taxes on capital gains and dividends.He said it is difficult to predict the amount of revenue that can be raised from closing loopholes and deductions in the tax code, so that discussion should be handled as part of a separate conversation about reforming the tax law.

“You don’t know the consequences when you start fooling around with the deductions and exemptions outside tax reform. So I think the easiest way is to raise rates,” Mr. Cardin said.

Seth McLaughlin contributed to this report.