"The more Republicans ask for a fight over the debt ceiling and play political games such as trying to dismantle health care reform, the more they own the results," they wrote. "And Republicans know they can't afford to be blamed for default."
The letter rallying Democrats comes just days before the government faces a possible shutdown, and with a major battle over raising the nation's $16.7 trillion borrowing limit just a few weeks away.
The Senate is expected this week to consider legislation funding the government beyond Oct. 1, after House Republicans approved a funding bill that prevents a shutdown through Dec. 15 but also defunds the president's healthcare reform law. The White House has threatened to veto that measure, and Senate Democrats have insisted the plan is dead in their chamber.
Meanwhile, the Treasury Department has called on Congress to raise the debt limit before mid-October, warning the government will run dangerously low on cash at that point and will struggle to keep up with its obligations. President Obama has insisted he will not negotiate over the debt limit.
To bolster the case for fiscal concessions, BoehnerJohn BoehnerHouse markup of ObamaCare repeal bill up in the air Conservatives to Congress: Get moving Boehner: ObamaCare repeal and replace 'not going to happen' MORE has highlighted previous times the debt limit was increased along with other fiscal reforms, arguing it is not out of the ordinary for Congress to seek fiscal fixes alongside a borrowing boost.
But Murray and Baucus included a memo with their letter that argues there have been plenty of times the debt limit has been boosted without a fiscal standoff.
In fact, Budget Committee staff determined that, since 1983, more than three-quarters of debt limit increases were not accompanied by deficit reduction or other budget reforms. And of the 31 debt limit boosts that happened without such reforms, a dozen were simply approved by voice vote, while a majority of Republicans backed 14 of the remaining 19.
The memo also argues that Republican plans to allow the Treasury to "prioritize" important payments if the debt limit were not raised are not workable, echoing similar complaints about such plans from the Treasury Department.
The continuing resolution passed by House Republicans on Friday included language that would allow the Treasury to continue borrowing funds above the debt limit if it were not raised but only to cover interest payments on debt and Social Security payments.