The Senate voted Monday to begin a rare, open-ended debate on immigration reform that both parties hope will end with a measure that can win 60 votes and ultimately become law.

“I’m not sure what’s going to happen because it’s been so long since we’ve tried this,” Minority Whip Dick Durbin, D-Ill., said. “But, it really is exciting to think about that men and women elected to this body, known as the greatest deliberative body in America, are finally going to deliberate.”

It’s been five years since Senate lawmakers debated a major immigration reform measure. As of Monday, no specific bill was introduced for a vote in the Senate, but several are likely to be introduced this week.

Lawmakers voted Monday to start debate using a shell bill and to introduce proposals as amendments. The proposal that can win 60 votes will pass and be sent to the House.

Lawmakers can introduce amendments after 30 hours of debate. If both parties agree to drop the 30-hour requirement, amendment debate can begin sooner.

“I hope this body can seize this opportunity and deliver real progress towards securing our border, reforming aspects of our immigration policy, and achieving a resolution for individuals who were brought to our country illegally when they were young,” Majority Leader Mitch McConnell, R-Ky., said. “The American people have heard no shortage of rhetoric on this issue. They have heard many of my colleagues across the aisle insist this issue requires swift action. Now it is time to back up this talk with the hard work of finding a workable solution.”

The two parties are aiming for a deal that provides protection from deportation for young people known as Dreamers, who came to America as children and are now legally protected under the Obama-era Deferred Action for Childhood Arrivals, or DACA, program.

To win the support of Republicans the deal must include border security and changes to chain migration, called family reunification by Democrats, and the visa lottery system.

Lawmakers are working under a March 5 deadline, when the court-challenged DACA program expires.

On Monday, McConnell announced his support for a bill that will be introduced by a group of Republican senators that mirrors the Trump administration's immigration reform framework.

The plan would provide a pathway to citizenship for 1.8 million people and would appropriate $25 billion for border security, including a southern wall or fencing. It would limit chain migration to spouses and minor children and end the visa lottery, using the annual 50,000 lottery openings to clear the current backlog of scrutinized visa applicants.

“It’s our best chance of producing a solution that can actually resolve these matters,” McConnell said. “Which requires that a bill pass the Senate and pass the House and earn the president’s signature.”

Sens. Jeff Flake, R-Ariz., Lindsey Graham, R-S.C., and Durbin are co-sponsors of another immigration bill that is likely to get a floor vote.

Their measure would provide a pathway to citizenship for Dreamers, but appropriates less than $3 billion for border security and impose less strict limitations on chain migration.

President Trump said he opposes the Graham-Durbin proposal.

Durbin told reporters Monday he may introduce a bill that includes nothing but language protecting the Dreamers, which is certain to fail but would put lawmakers on the record.

Another bill that will likely get a floor vote, authored by Sens. John McCain, R-Ariz., and Chris Coons, D-Del., would provide a pathway to citizenship for 3.2 million illegal immigrants and call for a study on the feasibility of a border wall.

Flake has introduced another measure that would provide a three-year extension of the DACA program in exchange for some border wall funding.

Floor debate comes after weeks of failed negotiations by various Senate factions as well as a bipartisan group of House and Senate leaders which included Trump administration officials. None of the talks produced a deal, and some top lawmakers are skeptical anything can pass this week.

“We will see what gets 60 votes,” Senate Majority Whip John Cornyn, R-Texas, said Monday.