(CNN) If Congress doesn't act this week, the federal government will shut down for the second time this year.

Lawmakers are up against two key deadlines that were put in place as part of the negotiations to reopen the government last month, creating a short window to show substantial signs of progress on a deal to protect undocumented immigrants who came to this country as children and their families. Immigration negotiators say they've taken steps in the right direction, but no deal to address the contentious issue has thus far emerged.

The first deadline is Thursday, when government funding runs out. The second is to reach a long-stalled deal on immigration before Senate Majority Leader Mitch McConnell opens a promised freewheeling floor debate to try to settle the contentious issue.

Congressional leader from both parties have said they don't foresee a second shutdown, but as of Sunday evening, it's not clear if congressional leaders have the votes to pass such a measure through both the Senate and the House.

Threat of shutdown

Will the government shut down? It's too early to know.

The House plans to vote on a short-term bill to keep the lights on through March 22, but Senate leaders have not committed to that bill, so negotiations will continue.

It is unclear whether House Republicans will even have the votes to pass the bill, as defense hawks and conservative House Freedom Caucus members are balking at approving another temporary solution. And since House Democrats are adamant they won't support a continuing resolution that does not include immigration reforms, it's possible GOP leaders will come up short of a majority when that vote takes place Tuesday.

If it does pass the House, 60 votes will be needed in the Senate, meaning at least nine Democrats must vote yes. It's too soon to know if they will back the House's six-week proposal, in part, because it blows past a March 5 deadline when the Deferred Action for Childhood Arrivals program expires.

Democrats may want to maintain some leverage to help keep DACA in place.

But Republicans feel confident Democrats won't threaten to shut down the government as they did two weeks ago.

"There's no education in the second kick of a mule," McConnell said about the short-lived shutdown.

And Senate Democrats' chief immigration negotiator, Dick Durbin of Illinois, told CNN anchor Jake Tapper on "State of the Union" Sunday morning that he does not anticipate another government shutdown.

"I don't see a government shutdown coming, but I do see a promise by Senator McConnell to finally bring this critical issue that affects the lives of hundreds of thousands of people in America, finally bringing it to a full debate in the Senate," said Durbin, who is Senate Democrats' minority whip. "That's what we were looking for when there was a shutdown. We have achieved that goal. We're moving forward."

On immigration, he said congressional negotiators are "making real progress" and saluted Republicans as well as his fellow Democrats for their work in the immigration talks, even if there has yet to be a deal.

Other related issues that must still be negotiated include a federal spending limit and disaster relief funding. Republicans are also hoping to attach longer-term funding for community health centers in the short-term bill. House Speaker Paul Ryan voiced optimism about nailing down a budget caps agreement, saying that a short-term continuing resolution would allow time for the Appropriations Committee to write an omnibus spending bill.

On a similar note, the Senate Subcommittee on Federal Spending Oversight and Emergency management will hold a hearing Tuesday to assess the cost to taxpayers of the spending uncertainty caused by governing through continuing resolutions and shutdown crises.

What about immigration?

John Thune, a member of Senate Republican leadership, told reporters last week that he favors narrowing the immigration debate from President Donald Trump's suggested "four pillars" to two: legal status for DACA recipients and border security.

The framework suggested by the White House would provide 1.8 million undocumented immigrants a pathway to citizenship in exchange for $25 billion for border security, in addition to the eradication of the diversity lottery and changes to so-called chain migration.

Democrats are wary of making the kinds of changes to family immigration -- also known as chain migration -- and the diversity lottery that Republicans are demanding, effectively stalling the talks and leading to Thune's suggestion to limit the reforms to DACA and border security.

But House Freedom Caucus Chairman Mark Meadows called Thune's suggestion a "nonstarter," saying that it would not get support in the House.

Aides say if an open-ended floor debate happens it will likely take place the following week, but it's not clear exactly how or for how long the debate would take place.

In the meantime, heavy negotiations are expected to continue this week among party leaders and the White House. A separate effort by a large bipartisan group of senators is also underway.

Durbin signaled some of the headwinds facing the President's plan, saying the proposed changes to the US immigration system were not acceptable.

"Understand what they are proposing," Durbin told CNN. "They want to cut legal immigration into the United States of family members, some of whom who have waited 20 years or month to join up with their families here. This is no longer about the security of the United States. It is not about competition for American jobs. It is an effort by them to make a different immigration policy in the future, one that envisions an America that is much different than it is today."

Russia investigation

Debate will continue over the release of a highly controversial memo by House Intelligence Republicans , which has heightened the partisan divide over the Russia investigation.

While Republicans lauded the White House's decision to release the memo, saying it highlights underlying problems with US surveillance and provides greater transparency, Democrats slammed the decision.

The House Intelligence Committee's top Democrat, Rep. Adam Schiff of California, told reporters Friday that the memo, which was spearheaded by Intelligence Committee Chairman Devin Nunes of California, "cherry picks" information from then-FBI Deputy Director Andrew McCabe's testimony and the introductory portion represents a "troubling breakdown of legal processes."

Democrats on the House Intelligence Committee are expected to push for a vote at a Monday committee meeting to release their memo rebutting allegations of the Nunes memo, a move that could put the issue back on Trump's desk this week.

Senate Majority Leader Chuck Schumer on Sunday called on Trump to support the release of the House Democrats' memo, calling it "a matter of fundamental fairness" to let the public see both sides of the issue.

Sexual harassment

The House will likely move forward on their sexual harassment legislation this week to reform the Congressional Accountability Act of 1995. Among the improvements proposed include barring members from the use of taxpayer funds to settle any future sexual harassment settlements and creating a more streamlined process for individuals to report claims.

House Democrats retreat