With a week remaining for the congressional "super committee" to strike a deficit-reduction deal, a top Democrat said his party is not in agreement on an offer.
"The fact of the matter is Democrats have not coalesced around a plan," said Clyburn, the No. 3 Democrat in the House, on Fox News Sunday.
"It's at a difficult point," acknowledged super committee member Sen. Pat Toomey (R-Pa.) on the show. "We've got a ways to go."
The committee is deadlocked as it struggles to overcome deep partisan divisions on tax and spending proposals to reduce federal deficits.
The committee faces a Thanksgiving deadline to reduce deficits by $1.5 trillion over the next decade, and most members remained in Washington this weekend as the largely secretive panel continued closed-door negotiations.
Failure could upset the financial markets during the holiday shopping season, and trigger forced cuts that both sides hope to prevent.
The Republican co-chairman of the bipartisan panel, Rep. Jeb Hensarling of Texas, said he remained optimistic despite what has been "a roller-coaster ride." (see video below)
"We haven't given up hope," Hensarling said on CNN's "State of the Union."
But Hensarling acknowledged the committee may be forced to punt its most difficult decisions on tax and entitlement reform into next year.
The panel has considered breaking the impasse with a two-step approach that would establish the outlines of a deal, but propel the partisan debate over taxes into the 2012 election season as committees in Congress hammer out the details. Such a framework was considered by President Obama and House Speaker Johh A. Boehner (R-Ohio), as a way around the stalemate during the summer debt ceiling debate.
"If this was easy, the president and the speaker of the House would have gotten it done themselves," Hensarling said.
Hensarling also said the panel must agree to fundamental structural changes to Medicare and the other health entitlement programs that are driving deficits.
"Unless we deal with that, frankly, we will fail," he said.
The two sides have been unable to forge an agreement, deadlocked mainly over the ratio of new taxes to spending cuts.
Compromising on such core issues is increasingly difficult as both parties face backlash from their party bases as the election season begins.
Republicans have shifted off their rigid anti-tax position to propose $250 billion in new tax revenues, largely achieved by limiting itemized deductions used mainly by wealthy households. That offer puts the GOP at odds with the "no-tax" pledge most lawmakers have signed with conservative activist Grover Norquist's Americans for Tax Reform.
"To get to where we need to be as a country, there's going to be required some compromise," said Republican Sen. Tom Coburn, the deficit hawk from Oklahoma, on CNN. "Will people do what's best for the country or best for their party and position?"
Democratic Sen. Mark Warner of Virginia, another deficit hawk, agreed that when constituents from the political bases of both parties are protesting the loudest, "you know the super committee is getting close" to a deal.
Obama called Hensarling and Sen. Patty Murray of Washington, the Democratic co-chair, as he departed for a weeklong Asia trip, urging them to keep working and warning against undoing the triggered cuts if the committee fails.
But because those future cuts are not scheduled to begin in 2013, many in Congress think they will not happen. The reductions would slice equally across defense and domestic programs, and defense hawks have begun working openly to spare the Pentagon from cuts.
Toomey said "it's very likely" those cuts will be reconsidered by Congress.
The super committee faces a Nov. 23 deadline to vote, but must post its proposal internally 48 hours ahead of time, which makes this week its final push for an agreement.
If a proposal is approved, the full Congress must vote on it by Christmas Eve.