WASHINGTON — President Barack Obama urged Congress on Monday to raise the nation’s debt ceiling without spending cuts, warning of dire consequences to the economy if lawmakers again push deliberations to the brink.

In the last news conference of his first term, Obama said he wouldn’t negotiate with congressional Republicans who want to use the obligation to lift the debt ceiling as an opportunity to curtail federal spending.

“They will not collect a ransom in exchange for not crashing the American economy,” the president said. “The full faith and credit of the United States of America is not a bargaining chip.”

The tough talk came as Obama prepares to take his second oath of office and a new fiscal crisis looms, just two weeks after he and Congress tussled over a New Year’s deal to avoid a series of tax hikes and deep spending cuts.

That deal didn’t include raising the $16.4 trillion debt ceiling, which the Treasury Department said was reached Dec. 31. Treasury has tapped emergency borrowing authority to pay creditors, but that fix is fast expiring and the president warned Monday that “time is running short.”

He urged Congress to raise the debt ceiling without conditions and focus on a new fiscal plan to reduce the budget deficit by cutting spending and raising new revenue. He argued that the results of the November election show that voters side with his economic prescription.

“It turns out the American people agreed with me,” he said. “They want us to get our books in order in a balanced way, where everybody pulls their weight, everyone does their part.”

He said he’d be open to “modest adjustments” to programs such as Medicare, but he argued that the deficit can’t be solved by spending cuts alone. And he argued that lawmakers would risk the nation’s reputation by haggling over the debt ceiling – risking a credit downgrade like the one imposed in 2011 after a fight over raising the debt ceiling.

“To even entertain the idea of this happening, of the United States of America not paying its bills, is irresponsible,” he said.

Obama argued that raising the debt ceiling pays for expenses that already have accrued, likening the debate to arguing over a restaurant check once the diner has polished off his plate. And he warned that failing to lift the ceiling might delay Social Security checks and veterans’ benefits.

He brushed aside suggestions from congressional Democrats that he invoke an obscure provision in the Constitution to pay increased debt without congressional approval. “There are no magic tricks here. There are no loopholes,” the president said.

“What I will not do is to have that negotiation with a gun at the head of the American people,” he said. “The threat that unless we get our way, unless you gut Medicare or Medicaid that we’re going to threaten to wreck the entire economy – that is not how historically this has been done. That’s not how we’re going to do it this time.”

Republicans reacted with some history of their own, noting that Obama had voted against raising the debt ceiling when he was a senator and George W. Bush was president.

“The president says he will not negotiate on cutting spending as part of raising the debt ceiling, but he voted against raising the debt ceiling as a United States senator,” said Rep. Cathy McMorris Rodgers, R-Wash., the chairwoman of the House Republican Conference.

“The president and his allies need to get serious about spending, and the debt-limit debate is the perfect time,” said Senate Republican leader Mitch McConnell of Kentucky.