Confident that taxes on high-income earners will go up even without a large bipartisan fiscal agreement, Democrats are digging in against Republican demands for further spending cuts.

GOP leaders are beating the drum for a reduction in domestic spending, with House Speaker John A. Boehner repeating his assertion on Thursday that the country has “a spending problem,” not a revenue problem. “The president wants to pretend spending isn’t the problem,” the Ohio Republican said. “That’s why we don’t have an agreement.”

But the calls haven’t succeeded in breaking through the seemingly solid resistance against cuts in popular programs such as Medicare, and top Democrats said Thursday that they have no plans to discuss concessions on spending, at least not until Republicans accept a tax rate increase on upper-income earners.

“We have the political high ground. There is no question about it,” said Sen. Charles E. Schumer, D-N.Y. “The sooner they realize it, the better it will be for them.”

With tax rates going up next year absent congressional action, a growing number of GOP lawmakers have said they would accept higher tax rates on high-income earners in return for changes to entitlement programs. Other Republicans have suggested simply passing a tax cut for the middle class but nothing else, with the hope of extracting spending cuts next year during a confrontation over raising the debt limit.

Schumer said Democrats should not consider wide-ranging measures to overhaul entitlement programs until Republicans endorse them first.

“The Republicans say there ought to be spending cuts, but they don’t put a single specific on the table,” Schumer said. “Now, what does that say? That says they know that the kinds of things they’re advocating might not be very popular.”

Democrats say the president has already shown a willingness to cut entitlement programs, although the emphasis would be on targeting providers rather than beneficiaries.

Rep. Chris Van Hollen, D-Md., noted that Obama proposed more than $600 billion in savings in health care and mandatory programs in his fiscal 2013 budget.

“I think you could get to the president’s number of $600 billion” in spending cuts in a deal, said Van Hollen, the ranking Democrat on the House Budget Committee. But Republicans want more spending reductions.

Although House Republican leaders have not publicly backed specific ideas, they have been pushing Obama to accept an increase in the eligibility age for Medicare, to 67 from 65, and a reduction in cost-of-living benefits for Social Security recipients. Obama tentatively endorsed both proposals as part of failed debt ceiling negotiations with Boehner last year. Requiring wealthier Medicare beneficiaries to pay higher premiums is another oft-discussed way to target entitlement programs.

Senate Majority Whip Richard J. Durbin, D-Ill., told reporters on Thursday he’d heard that the White House had taken an increase in the Medicare eligibility age off the negotiating table.

Durbin, a close Obama ally, later said that was a rumor and that it had not come from the White House. Still, he said he opposed an eligibility-age boost and was skeptical of working to overhaul Medicare and Social Security in the waning days of the lame-duck session.