Senate Majority Whip Richard J. Durbin, D-Ill., hits the gym before 6 a.m. So does Sen. Marco Rubio, R-Fla. It was there that two of the eight members of the Senate’s immigration working group began chatting about the issue.

“It’s funny how it happened,” Durbin said. “I open up the Senate gym in the morning … at 5:30, and he usually shows up a little bit before 6. So we’ve come to know one another.”

Rubio said he felt comfortable joining the group after talking with Durbin.

“I expressed to him my principles and where I was headed with [my legislation], and he felt that that fit in with what they were working on, so I joined those conversations,” Rubio said.

Group members Sens. Robert Menendez, D-N.J., and Lindsey Graham, R-S.C., also talked in the Senate gym about the issue.

Those friendships formed over workouts have helped foster the best chance of passing an immigration overhaul in six years. After releasing a framework last month, the group hopes to have a draft bill by March. President Barack Obama is pressing them to stick to that plan. Obama has warned that if the talks stall, he will unveil his own bill, the details of which leaked this weekend.

But each member of the group is optimistic that their bill can pass with broad bipartisan support, and their own unique history with the issue may help to get it across the finish line.

Sen. Michael Bennet, D-Colo.

Bennet came to the issue as superintendent of Denver Public Schools, where he saw the effect on families under the threat of deportation. Hispanic students made up more than half of the student body in Denver as of October. Soon after Bennet was appointed to the Senate in 2009, he met with activists and embraced changes and the DREAM Act, which would set up a path to citizenship for undocumented immigrants brought to the United States as children. Bennet, along with Senate Majority Leader Harry Reid, D-Nev., early on saw the value of championing the issue in statewide campaigns, and Latino voters propelled him to a full term in 2010.

Sen. Richard J. Durbin, D-Ill.

For more than a decade, Durbin has been pushing a version of his DREAM Act, and he has become the unofficial representative in the Senate of so-called Dreamers, who have been increasingly vocal about their plight. Durbin is also a veteran of past immigration overhaul fights and has good relationships with the other members of the group. He said he sought out Sen. John McCain, R-Ariz., after the elections to discuss the issue and see what could be done: “We’ve been in this business for a while, every immigration bill that’s been around since I was elected I’ve played [at least] a small part in, and John’s been at the table every time.”

Sen. Jeff Flake, R-Ariz.

A staunch conservative, Flake is a good example of a Republican from a heavily Hispanic state who sees the issue as an imperative for national policy. As a House member, Flake worked with Rep. Luis V. Gutierrez, D-Ill., and Sen. Edward M. Kennedy, D-Mass., on immigration issues in the last major push in 2007. He cooled to comprehensive overhaul during his bid for the Senate last year, but he said recently that his current involvement should be expected. “If you’re from Arizona and you’re not involved in something of this magnitude and you can be, then you’re not representing your state very well,” he said.

Sen. Lindsey Graham, R-S.C.

A longtime supporter of immigration overhaul, Graham joined the group despite the possibility of a primary challenger in his 2014 race. Graham said it would be disingenuous and “bad politically” for him not to be part of the group. “I’m associated with the issue,” he said. The issue may not play well in South Carolina, but Graham notes his high-profile criticism of the White House’s handling of the Benghazi, Libya, terrorist attack. “I have no problem pushing the president on Benghazi, no problem standing up to a lot of his policies,” Graham said. But, “It’s just as good politics for me to solve a hard problem working with the president and Democrats.”

Sen. John McCain, R-Ariz.

Getting a bill into law could cement McCain’s legacy in the Senate and help the Republican Party remain competitive in future elections as the number of Hispanic voters increases. But McCain downplayed that aspect when asked about it. “I’ve been involved with it for many years, and I think it’s ripening,” he said. “And when you’re from a state like mine, it’s particularly important.” Like Flake, McCain distanced himself from a comprehensive overhaul during his 2010 re-election campaign and in his 2008 campaign for president. Still, it remains to be seen whether McCain commands enough influence to bring along more GOP votes in the House and Senate.

Sen. Robert Menendez, D-N.J.

Menendez has long been an aggressive advocate of an overhaul, and he’s one of the few members of the group to offer his own bill on the issue in the past three years. Menendez, who is of Cuban ancestry, is one of only two Latino members of the Senate, giving him instant credibility. Over the years, Menendez has earned the trust of liberal immigration advocates, who will be looking for his approval as a sign that their interests have been taken into account. Menendez also has an established working relationship with Rubio, as the chairman and ranking member, respectively, of the Foreign Relations subcommittee over Latin America.

Sen. Marco Rubio, R-Fla.

Rubio, who is also of Cuban descent, is the group’s bridge to the conservative wing. He was in the mix to be GOP presidential nominee Mitt Romney’s running mate and has been floated as a presidential contender for 2016. Rubio conceded that being in the group could benefit him if he seeks higher office. However, he stressed that he’s involved because “This is a major issue that impacts my state and one that I think I am expected to play a role in trying to solve. If I do a good job at this  . . .  I am sure I will have opportunities to do other things in the future — be it re-election, leaving politics  . . .  or running for another office.”

Sen. Charles E. Schumer, D-N.Y.

Schumer was involved in passing the 1986 overhaul bill as a member of the House Judiciary Committee, and he has remained active throughout the decades, including introducing a bill in 2010. His lasting interest is reflected in his 2009 decision to give up a Banking subcommittee chairmanship to retain the gavel of Judiciary’s immigration subpanel. Leading the immigration push could help Schumer soften his reputation as a partisan attack dog. It would also pad his legislative résumé. While he has managed to become the No. 3 Senate Democrat, he has relatively few major legislative accomplishments.

This story has been corrected to reflect the members who have introduced immigration bills in recent years.