“In the event that Republicans make good on their threat by failing to act, or by moving unilaterally to pass a debt limit extension only as part of unbalanced or unreasonable legislation, we believe you must be willing to take any lawful steps to ensure that America does not break its promises and trigger a global economic crisis — without Congressional approval, if necessary,” Senate Majority Leader Harry Reid (D-Nev.) and other Democratic leaders wrote in a letter dated Jan. 11.

Senate Democratic Whip Dick Durbin (Ill.), Senate Democratic Policy Committee Chairman Charles Schumer (N.Y.) and Democratic Conference Secretary Patty Murray (Wash.) signed the letter.

“It is hard to imagine that the Speaker and Leader McConnell would really follow through on their threat to let our nation default on its debts. They are responsible leaders who know better,” they wrote in reference to Speaker John Boehner (R-Ohio) and Senate Republican Leader Mitch McConnell (Ky.).

“Sadly, some of their Republican colleagues do not. Therefore, we believe that you must make clear that you will never allow our nation’s economy and reputation to be held hostage,” they wrote in a not-so-veiled reference to Tea Party-affiliated conservatives in the House.

House Democratic Leader Nancy Pelosi (Calif.) said last week she would invoke the 14th Amendment if given the choice.

“I've made my view very clear on that subject: I would do it in a second,” Pelosi told reporters Jan. 4. “But I'm not the president of the United States.”

Reid has changed his mind on the issue over the past 18 months. In the summer of 2011, he said Obama should not use the 14th Amendment to circumvent Congress.

"We should play by the rules," Reid told reporters at a press conference in July of 2011.

Obama rejected the prospect of raising the debt ceiling on the basis of the 14th Amendment when some Democrats suggested it at the time.

“I have talked to my lawyers,” Obama said in the summer of 2011. “They are not persuaded that that is a winning argument.”