US President Barack Obama meets US Senate Democrats including Senate Majority Leader Harry Reid (D-NV) (R) in the Oval Office of the White House in Washington, October 12, 2013.[Photo/Agencies]

WASHINGTON — Senators put faith in party leaders Sunday to devise a plan that would reopen the government and steer clear of a potential default this week, saying it's unthinkable that political obstinacy would prevent the United States from paying its bills.

With House leaders sidelined, Senate Majority Leader Harry Reid, D-Nev., and Senate Minority Leader Mitch McConnell, R-Ky., have taken the lead on discussions in the fiscal crisis. That raised the level of optimism among some senators that a deal could be reached even as Reid has said there was a "long ways to go" and few details on the leaders' talks have emerged.

"It's a breakthrough. Hard to imagine, but it's a breakthrough," said Sen. Dick Durbin, the No. 2. Senate Democratic leader, on NBC's "Meet the Press."

Sen. Rob Portman, R-Ohio, predicted a short-term solution could be reached. "We will figure it out," Portman said.

Though the Senate was leading the search for a deal, the House and its fractious Republicans remained a possible headache in the coming week.

"I think at this point we've got to figure out a way to get something out of the Senate that we think is close enough for the House to accept," Sen. Bob Corker, R-Tenn., said on "Fox News Sunday."

Sunday marked the 13th day of a federal shutdown that has continued to idle 350,000 government workers, left hundreds of thousands of others working without pay and curtailed everything from veterans' services to environmental inspections. Last week, the effects of the shutdown reached businesses, such as concessions and hotels near federal parks, that depend on government programs.

More ominously, Thursday's deadline to raise debt ceiling drew another day closer, the day the Obama administration has warned the US will deplete its borrowing authority and risk an unprecedented federal default. Economists say that could send shockwaves throughout the US and beyond.

The pressure was on both parties but seemed mostly on Republicans, who polls show are bearing the brunt of voters' wrath over the twin standoffs. And though the financial markets rebounded strongly late last week on word of movement in the talks, lawmakers of both parties were warily awaiting their reopening this week to another impasse.

Republicans are demanding spending cuts and deficit reduction in exchange for reopening the government and extending its borrowing authority. President Barack Obama and other Democrats say they want both measures pushed through Congress without condition and would agree to deficit reduction talks afterward.

Out of play, for now, was the Republican-led House, where Speaker John Boehner, R-Ohio, told GOP lawmakers early Saturday that his talks with the president had ground to a halt.

Also sidelined, at least for now, was a plan forged by Sen. Susan Collins, R-Maine, and a bipartisan coalition to briefly fund the government and extend the $16.7 trillion debt limit, in exchange for steps like temporarily delaying the medical device tax that helps fund the health care law.

Democrats said Collins' plan curbed spending too tightly, and Reid announced Saturday it was going nowhere.

Collins said Sunday that both Democrats and Republicans continue to offer ideas and say they want to be part of the group working to reopen the government and address the debt ceiling before Thursday's deadline.

"We're going to keep working, offering our suggestions to the leadership on both sides of the aisle in an attempt to be constructive and bring this impasse to an end. Surely we owe that to the American people," Collins said on CNN's "State of the Union."

Sen. Amy Klobuchar, D-Minn., said she sees the Collins plan and the fact that the Senate leaders are talking as a positive going forward.

"We need that right now," she said, adding that while Reid wouldn't accept everything in the Collins plan, "he knows there are some positive things in that plan," such as opening the government in a "smart time frame" not defaulting on debt and doing something in the long term on the budget.

Senate Republicans dealt Democrats an expected setback on Saturday by derailing a Democratic measure extending the debt limit through 2014 without any conditions. The vote was 53-45 to start debating the Democratic measure — seven short of the 60 votes needed to overcome GOP obstruction tactics.