(CNN) It's three days until a potential government shutdown and Republicans are still charting a path forward to head off the looming crisis.

GOP leaders negotiated Tuesday with the conservative House Freedom Caucus to try to convince them a two-week must-pass spending bill that leaders are advocating won't lead to the conservative group being jammed by a second pre-Christmas spending bill chalk full of controversial policy items.

Freedom Caucus members said they were primarily concerned that the two-week bill -- which would fund the government through December 22 -- would force them to later accept another short-term bill to keep the government open into the New Year that includes immigration policy, an Obamacare stabilization package and a variety of other supplemental spending right before members rush to get home for the winter holiday break.

On Tuesday, the House Rules Committee postponed its consideration of the two-week bill to give leadership more time to work with rank-and-file members, a sign that more work still needed to be done.

After getting assurances from leadership, some Freedom Caucus members seemed to warm to the idea of a two-week bill, instead of a three-week bill they had pushed for that would have kept the government funded until December 30. On Monday night, in protest of the shorter bill, Freedom Caucus members nearly sank a procedural vote to go to conference committee on the recently passed tax bill.

"There would have to be some iron-clad commitments from leadership on how this would be different than the last five years," said the group's chairman, Rep. Mark Meadows, a Republican from North Carolina.

Rep. David Brat, a member of the House Freedom Caucus from Virginia, said conservatives wanted assurances that House GOP leaders would try to pass a bill with a majority of Republican votes and not rely on Democrats to get it through.

In addition, conservatives have a core frustration that Senate GOP leaders made assurances to some of their members -- like Sen. Susan Collins of Maine to get their tax bill done -- without consulting the House. Senate leaders promised Collins they would support a plan to stabilize the Obamacare marketplace and restore funding of what are known as cost-sharing reduction payments, something many conservatives oppose.

"So, the Senate doesn't do a budget in the first place and then they're doing triple bank shots and we got to go with that? I don't think so," Brat said. "I don't think the American people voted on bailing out big insurance."

In the Senate, several senators balked at the idea of a December 30 spending bill with Majority Leader Mitch McConnell, R-Kentucky, saying he preferred a deal to December 22.

"The date hasn't been set yet. That's what we're talking about. My preference would be a two-week CR into December 22," McConnell said, referring to a continuing resolution.

Republicans have also been clear that they don't want to muddy the waters of a spending deal with a controversial negotiation on what to do about recipients of the Deferred Action for Childhood Arrival program , those individuals who came to the country illegally, but were given protected status under the Obama administration. That program is set to expire in March.

"It simply does not advance the interests of these DACA recipients to try and force this into a shutdown narrative and to jeopardize our national security and other government functions just in order to help these young adults," Senate Majority Whip John Cornyn said Tuesday. "We are certainly willing to enter into those good-faith negotiations, but they do not belong in the end-of-the year spending appropriations debate. I hope our colleagues on the other side of the aisle will take our word for it as demonstrated by our good faith in making an offer to them that we do want to resolve this but it's not going to be before the end of this year. "

Democrats remain the other wild card in the negotiations. Many are insisting that some kind of deal on immigration must be approved by the end of the year and have warned they might force a government shutdown if they don't get their way. Even if Republicans can pass a two-week spending bill on their own in the House, Democrats are still needed to pass the bill in the Senate.

And, there are still questions about what would follow a two-week stopgap spending deal.

Even if they get the two-week deal, leaders will have to find a solution avert another possible shutdown after December 22.

"I hate to see us have to kick the can twice, but apparently we're going to have to kick the can twice," said Sen. Roger Wicker, a Republican from Mississippi.

Democratic leaders Sen. Chuck Schumer and Nancy Pelosi are scheduled to meet with Trump Thursday . They both have been noncommittal about where they stand on the spending negotiations.

"We don't know what the House is going to do. But if it's a short-term CR, it gives us a little more time to do the things we're talking about," Schumer said.

Multiple House Republicans were pressing leaders to follow the two-week measure with another spending package that included increased money for the military, along with more disaster aid for states and US territories still recovering from a series of devastating hurricanes. Democrats would likely oppose that approach because it doesn't address DACA.

House Armed Services Chairman Mac Thornberry, a Texas Republican, told reporters he wanted to approve the defense spending soon so "it's not a political football for everybody else's agenda."

Given the divisions inside the House GOP conference on spending bill votes, Democrats traditionally back stopgap bills to avoid any threat of a shutdown. But the number two House Democrat suggested that the GOP could be on their own this time, as Democrats don't have any details about the strategy going forward.

Pointing out the GOP controls "every lever of government" Rep. Steny Hoyer, a Maryland Democrat, said: "Republicans need to take responsibility. We'll see what happens."