In a furious round of last-ditch negotiations, Senate Majority Leader Harry Reid and Minority Leader Mitch McConnell were discussing a proposal to reopen the government until Jan. 15 and extend the national debt limit until Feb. 7. The plan would also set up bicameral budget negotiations over major deficit issues, that are to conclude by Dec. 13.

There were still minor sticking points Monday evening, including over whether to change the law to prevent the Treasury Department from using “extraordinary measures” to go beyond the new Feb. 7 debt limit deadline, a change McConnell was pursuing. But the White House and Reid are strongly opposed to that idea, and several Democratic sources insisted such a provision would not be included in the final package.

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Indeed, there were growing expectations that a deal was imminent; Senate Republicans and Democrats are expected to meet Tuesday to discuss the proposal in separate closed-door caucus meetings.

The prospects for the emerging Senate deal in the GOP-led House are far from certain. And there’s a risk that major fiscal decisions are again being punted to a later time.

While Republicans failed to win the adoption of any proposals to gut or delay Obamacare, a chief demand that started the shutdown fight, two other provisions to tweak the law remained in play Monday night.

Under the emerging deal, Republicans would win a provision to force Kathleen Sebelius, the Health and Human Services secretary, to certify that individuals receiving Obamacare subsidies meet the required income levels. The department’s inspector general would later have to conduct an audit on the matter.

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But sources said Monday night that the GOP would only win that proposal if Democrats won the inclusion of a provision to delay the law’s so-called “belly button tax” for one year. The tax, which was supposed to be levied against most insurance plans to help spread the risk for insurers who take on the sickest patients next year, would cost covered individuals $63 per year. Republicans were balking at the proposal they called a carve-out for big labor unions.

If the two sides can’t agree on both provisions, it’s possible both Obamacare-related proposals could be dropped from the final package.

After meeting twice Monday and speaking repeatedly through aides and by phone, Reid and McConnell both were hopeful a deal would reached when they adjourned the Senate for the evening.

“We’ve made tremendous progress. We are not there yet but tremendous progress. And everyone just needs to be patient,” Reid said. “We’re doing our best to make everybody happy but everyone knows we’re not going to be able do that. So everybody understand we’re doing the very best we can with all the frailties that we have as people and legislators.”

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“We’ve made substantial progress, and we look forward to making more progress in the near future,” McConnell said.

McConnell is keeping in close touch with House Speaker John Boehner as negotiations with Reid continue. Boehner (R-Ohio) stopped by McConnell’s office for about 25 minutes on Monday afternoon.

In a sign a deal was taking shape, President Barack Obama delayed a Monday meeting at the White House with the congressional leaders to give Reid and McConnell more time to finalize an accord.

White House Deputy Chief of Staff Rob Nabors was at the Capitol on Monday evening and told reporters he’s “optimistic.”

“I’m not sure what the hang-up is but it seems Sen. McConnell and Sen. Reid are working well together,” he said. “It feels like we’re in a good position.”

Under the plan, the government would be funded at $986 billion until Jan. 15, the same day that a $21 billion across-the-board sequestration cut is slated to take place. Indeed, by aligning the government funding fight with the date that the next sequester is supposed to hit, it all but ensures a heated fight over whether to continue the unpopular cuts in the new year. Doing so would lower 2014 funding levels to $967 billion, a level far too low for many Democrats.

And by extending the debt ceiling until the beginning of next year, it would put the issue in the center of the heated 2014 midterm elections. The plan also would give federal agencies more discretion to implement the across-the-board sequestration cuts in 2014.

House Republicans already seemed cool to the proposal Monday afternoon, as several aides said the chamber would consider amending any Senate proposal.

“If the Senate comes to an agreement, we will review it with our members,” said Michael Steel, a spokesman for Boehner.

But meddling with the Senate plan could risk a default on the $16.7 trillion national debt, while prolonging a bitter fight over the government shutdown that has damaged the GOP brand.

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The clock is running out. Any bipartisan agreement needs to come together very soon – either Monday or Tuesday – or else the nation runs a serious risk of running out of the ability to borrow money as soon as Thursday. In 2011, a last-minute deal to lift the debt limit resulted in a credit downgrade of U.S. debt.

The timing for a vote in the Senate is unclear. If any senator objects, it could drag out the process until after the Thursday deadline to avert a potential default; otherwise, a vote could occur imminently. The Senate is expected to vote on the measure before the House, aides said Monday evening.

If Reid and McConnell are able to reach an agreement, it will put pressure on Boehner to act — even if it requires allowing a vote on a deal that’s not supported by a majority of House Republicans.

While the proposal has similarities to one offered by Sen. Susan Collins (R-Maine) last week, it has some very key differences over the length of the stop-gap spending measure and the debt ceiling hike. Collins proposed extending government spending for six months, which Democrats objected to because they argued it would lock in the $967 billion sequestration levels for 2014 required under the 2011 Budget Control Act. She also suggested extending the debt ceiling through the end of January, and the emerging deal appears to hew closely to that timeframe.

Because the prospective deal would not gut Obamacare, tea party conservatives will likely attack the proposal as too weak to support. But Republicans already began making the case that they were able to at least win some Obamacare concessions even if it doesn’t derail the law.

Democrats, too, appeared close to winning an Obamacare concession for labor unions. Just last month, the White House rejected pleas from labor leaders to allow their members to get Obamacare’s tax subsidies. The law doesn’t allow participants in multi-employer plans to get subsidies — a slight that unions said would lead to a breakdown in their health plans. But delaying the reinsurance tax would be viewed favorably by many of their allies in labor, even as it would anger insurance companies.

On another track, House Republican leadership is readying itself to lift the debt ceiling for six weeks. House GOP aides stress that no decisions have been made, but this legislation is unlikely to be “clean” – meaning it will contain a number of conservative policies attached. Options under consideration include language to cancel health insurance subsidies for members of Congress, their aides and the White House, and an amendment to tighten requirements for health-insurance related subsidies.

House Republicans are expected to meet Tuesday morning to discuss their options.

Ginger Gibson, Jennifer Haberkorn and Seung Min Kim contributed to this report.

Correction: A previous version of this story incorrectly attributed a quote about “frailties that we have as people and legislators” to McConnell that had been said by Reid.