Free-for-all Senate immigration debate kicks off

— -- In a rare move, the Senate will launch an unusual process late Monday afternoon to debate a legislative fix for the hundreds of thousands of so-called Dreamers who could face deportation come March 5.

The process calls for a free-for-all debate on the Senate floor with an unlimited number of amendments that can be offered, all in the hopes Republicans and Democrats can reach a bipartisan solution in the contentious immigration debate.

“I expect that virtually every issue under the sun will come up during this floor debate and that's fine,” Sen. Susan Collins, R-Maine, told reporters last week. “That's the way the Senate always used to operate, that is a good way to legislate.”

The fate of Dreamers has riled Republicans and Democrats across the political spectrum. In January, the federal government briefly shut down, with both sides refusing to budge on the Dreamer issue despite weeks of negotiating.

At the time, Senate Majority Leader Mitch McConnell, R-Ky., promised Democrats a debate and a vote on Dreamers should the government remain open and funded.

McConnell has kept his word and last week told reporters the debate this week would be “fair to everyone in the Senate.”

“Whoever gets to 60 votes wins,” he said. “And it will be an opportunity for 1,000 flowers to bloom.”

The move is seen as a rare gamble by the usually cautious McConnell, because it’s not clear what the end result will be, but his decision to open the Senate floor up to debate has already won the approval of some Democrats.

“I think that Mitch McConnell has been a champ to say we're gonna do the process, we're gonna let amendments be offered, and whatever gets 60 votes will be what passes,” Sen. Bill Nelson, D-Fla., said last week.

Some senators involved in a bipartisan working group, which includes more than two dozen senators, have said they are optimistic they can come to some sort of a moderate solution to help Dreamers avoid deportation, but they acknowledge they haven’t reached a consensus on what the legislative framework should look like.

“If we're gonna do this in this short period of time, this can't be viewed as comprehensive immigration reform,” Sen. Angus King, I-Maine, said last week following a working group meeting.

“It's got to be a more narrow field, and then we can all talk about comprehensive immigration,” he said.

The bipartisan working group has signaled that, so far, a pathway to citizenship for Dreamers and enhanced border security are on the table.

But another group of conservative Republican senators want to take it a step further, by mirroring the framework the Trump administration has called for, including ending “chain family migration” and the diversity visa lottery program. Their proposal also includes a pathway to citizenship for 1.8 million Dreamers and $25 billion for border security.

“President Trump has been very clear on what he will sign into law, and this is it,” Sen. David Perdue, R-Ga., said in a statement. “This is a great deal and the only solution that fully addresses the four pillars in the President’s framework.”

On Monday, McConnell announced his support of the conservative proposal on the Senate floor, and said he thinks it has the best chance of getting signed into law by the president.

"I support the president's proposal and my colleagues' legislation to implement it. The Secure and Succeed Act is fair and addresses both sides' most pressing concerns, conforming to the conditions the president has put forward," McConnell said.

"It’s our best chance of producing a solution that can actually resolve these matters - which requires that a bill pass the Senate and pass the House and earn the president’s signature," he went on.

Moments later, the Senate's top Democrat, Chuck Schumer, D-N.Y., warned against conservative "overreach" in trying to reform the entire legal immigration system. He urged his colleagues to focus on a "narrow" bill instead.

During an infrastructure event at the White House Monday morning, Trump touted his position on DACA, the Deferred Action for Childhood Arrivals program he moved to end, which puts the fate of the hundreds of thousands of undocumented immigrants who came to the United States as children into peril.

"We have our military taken care of, we start very serious DACA talks today," Trump said. "We are - I can tell you, speaking for the Republican Party, we would love to do DACA. We would love to get it done. We want border security."

The Senate is expected to act before, and independently of, the House, where Speaker Paul Ryan has promised lawmakers he’d tackle a solution for Dreamers upon successful package of the spending deal, which passed in both chambers and was signed into law late last week.

Ryan and other GOP leaders are aligned with conservatives in the Senate, and insist that a House bill address the four pillars of reform that President Trump wants.

The so-called "number twos" in the House and Senate – Sens. John Cornyn, R-Texas, and Dick Durbin, D-Ill., and Reps. Kevin McCarthy, R-Calif., and Steny Hoyer, D-Md. – have worked for weeks with Secretary of Homeland Security Kirstjen Nielsen and White House chief of staff John Kelly on a separate bipartisan solution, though those negotiations stalled during the shutdown showdown last month.

“The issues are very difficult, they're very inter-connected, they're emotional. They're expensive, in some cases. But we do seem to be making progress,” Collins said.

But there may be a reprieve for DACA recipients if Congress can't come up with a solution by the March 5 deadline.

In January, a federal judge temporarily blocked the Trump administration's plans to rescind DACA protections.

The judge that issued the nationwide injunction, wrote "that the rescission [of DACA] was arbitrary and capricious.”

The White House called the ruling “outrageous” and said in a press statement that “an issue of this magnitude must go through the normal legislative process.”

The Justice Department appealed to the 9th Circuit Court of Appeals, which it was required to do in order to ask for a direct review at the Supreme Court.

ABC News' John Parkinson, Geneva Sands, and Audrey Taylor contributed to this report.