Senate Democratic leaders urged President Barack Obama on Friday to be prepared to lift the debt ceiling “without congressional approval” if Republicans block legislation and default is imminent.

The letter from Majority Leader Harry Reid of Nevada and other Democratic leaders signaled they are taking seriously warnings from Republicans who have said they might be willing to see the government shut down rather than allowing a debt ceiling increase without concessions from Obama on spending cuts.

The letter also signed by Majority Leader Richard J. Durbin of Illinois, Charles E. Schumer of New York and Patty Murray of Washington counters the GOP threat with an equally tough stance, saying the president should “take any lawful steps” needed to avoid default.

Senate Minority Leader Mitch McConnell, R-Ky., called the Democratic leaders’ position “not only the height of irresponsibility, but also a guarantee that our national debt crisis will only get worse.”

The government hit the debt celing at the end of December, but the Treasury has said that “extraordinary measures” will delay a crisis until about the end of February.

House Speaker John A. Boehner, R-Ohio, has said he will push for a dollar in spending cuts for every new dollar in borrowing authority, a formula he came up with during last year’s debt ceiling debate. “The American people will not tolerate an increase in the debt limit without spending cuts and reforms,” Boehner aide Michael Steel said in response to the Democrats’ letter. “Washington Democrats must stop spending money we don’t have.”

Read More: