Senate Majority Whip Dick Durbin (D-Ill.) on Tuesday floated an idea that he called “pretty basic, and maybe radical.” (Scott Olson/Getty Images)

The biggest problem left for Congress to tackle, though, is the same issue that brought about the joint committee’s formation in the first place: the national debt, now at $15 trillion (and growing).

Now that the supercommittee has come up short, how should Congress proceed on the debt issue?

Senate Majority Whip Dick Durbin (D-Ill.) on Tuesday floated an idea that he called “pretty basic, and maybe radical”: Let any bipartisan group of 12 senators — six Republicans, six Democrats — who are able to agree on a proposal bring it to the Senate floor for a vote.

“I think we ought to say after February first of next year, any 12 senators, six of either party, who produce a plan that can reduce this deficit by at least as much as the supercommittee was charged to do, ought to be able to bring it to the floor for a vote,” Durbin said on MSNBC’s “Morning Joe.”

Durbin, who was part of the bipartisan “Gang of Six” senators working earlier this year toward a deficit-reduction plan based on that of the Simpson-Bowles commission, noted that the group of three Republicans and three Democrats grew to win the backing of some four-dozen senators of both parties. In September, 36 of those senators held a news conference urging the supercommittee to “go big.”

“I basically said to them, if the supercommittee doesn’t produce, now it’s our turn,” Durbin said Tuesday. “Put it on paper. Put it up for a vote. And I think that is the best way to move this forward and maybe restore a little bit of confidence in Congress.”

Several other lawmakers in the days since the supercommittee’s failure have called for Congress to take a vote on the Simpson-Bowles plan, which would achieve $4 trillion in deficit savings over the next decade through a mix of spending cuts, new revenue and reforms to federal entitlement programs.

Sens. Mark Kirk (R-Ill.), Lindsey Graham (R-S.C.) and Mark Udall (D-Colo.) issued statements Monday night urging for such a vote, and even before the supercommittee’s collapse, Sen. Joe Manchin (D-W.Va.) on Monday morning penned a letter to President Obama and congressional leaders urging for the Simpson-Bowles plan to be brought to the floor.

Decisions on what legislation makes it to the floor for a vote are made by party leadership in each chamber — and so far, the Gang of Six has yet to produce the legislative language for its plan.

But if the legislation does eventually make its way to the floor in either chamber, it could present a defining moment in the debt debate. More than 100 bipartisan House members and 45 senators signed onto separate letters calling for the supercommittee to “go big.” At the same time, many of those lawmakers have also pledged not to raise taxes or overhaul entitlement programs. A vote on Simpson-Bowles or any of the other far-reaching debt-reduction plans out there would up the pressure on lawmakers to make a choice between those two options.

Of course, such a vote could open up a whole new debate on what should or should not be included in a debt-reduction deal. In an appearance with Rep. Loretta Sanchez (D-Calif.) on Fox Business Network Tuesday night, Rep. Michael Burgess (R-Texas) took aim at the Simpson-Bowles plan for not including changes to last year’s health care reform law.

“You know, one of the things that has troubled me throughout all this discussion, the Simpson-Bowles commission, even the deficit commission — no one was ever willing to put any part of the Affordable Care Act on the table,” Burgess said. “And realistically, if you’re not willing to touch that, you haven’t been serious the whole time.”