As a Senate panel kicked off what could be weeks of meetings to work through a bipartisan overhaul of the nation’s immigration laws Thursday, there were no shortage of interested observers, including Sen. Marco Rubio.

But the Florida Republican had to sit on the sidelines as Judiciary Chairman Patrick J. Leahy, D-Vt., gaveled in the first meeting to amend a bill that Rubio has staked much of his political capital on. Because he is only a member of the bipartisan “gang of eight” who wrote the measure, and not a member of the committee, Rubio found himself watching it on TV.

Still, Rubio told CQ Roll Call in an interview that he was encouraged by the tenor of the meeting and the progress made on the first day of what is likely to be a long slog to the Senate floor.

“I’ve watched some of it on television,” Rubio said. “I’m really excited about Sen. Grassley’s amendment that really improves the bill by requiring that all nine sectors of the border be secured, not just the high-risk sectors.”

Iowa Republican Sen. Charles E. Grassley, the panel’s ranking member, filed 77 amendments for possible consideration by the committee, though it wasn’t clear how many of the 301 total amendments would be offered.

The gang of eight met as a group Wednesday night, and Judiciary member Charles E. Schumer told reporters those meetings would continue to keep everyone in the loop about amendments that they may find a need to oppose as a group.

“It’s largely just for those of us who are not on the committee to be informed about the amendments that are coming up,” Rubio said.

Rubio also was prepared to counter arguments made by some fellow conservatives opposing the gang’s plan, alluding in the interview to a Grassley proposal that the border be secured before anyone currently undocumented gets provisional status.

“The essence of it would be that all of the security measures would have to happen before we legalize anyone,” Rubio said. “The problem is that the funds that are being used to pay for all of those things are coming from the fines that those who are illegally here are paying in. So, the only way that we’re going to be able to get that money to pay for all of that stuff is to actually start that process.”

Losing Sleep

With the committee moving through the bill section by section, the most contentious issues won’t really come up until next week. For instance, treatment of immigrants in same-sex marriages remained an unresolved question, with Leahy deferring his decision on whether to call a vote on his Uniting American Families Act in committee.

Schumer told reporters he had literally lost sleep over the amendment, saying that it creates a conundrum because he and the other Democrats in the gang of eight viewed the issue as a matter of civil rights for gay couples, though GOP senators in the gang saw it as a non-starter.

“I’m a good sleeper, but I wake up in the morning thinking of these things — sometimes early in the morning. Our four Republican colleagues [in the gang of eight] feel very strongly that … if this is in the bill they would not be able to support it,” Schumer said. “Our four Democratic colleagues, including myself, believe that this is not just another issue, but an issue of discrimination.”

“We have to have a bill that has support to get UAFA passed. That’s the conundrum, because if there’s no bill, there’s no UAFA either,” Schumer explained.

Advocates know they have no chance of winning over some senators while maintaining the bill’s framework, which they say must include an eventual way for upward of 11 million individuals already in the country to attain citizenship, a point that Sen. Ted Cruz, R-Texas, thought would cause trouble in the GOP-led House.

“I’ve introduced amendments to remove the path to citizenship for those who are here illegally and make them ineligible for means-tested government benefits. If those provisions are insisted upon, and the majority has the votes to insist on those provisions, it is likely to scuttle this bill and cause it to be voted down in the House of Representatives,” he said.

“The $64,000 question here is how the mainstream and even more conservative ends of the party that know they have to have a bill deal with the hard right who’s against it,” Schumer said.

Utah Republican Sen. Orrin G. Hatch, whose vote some in the gang of eight think they could win, said in his opening statement Thursday that he hoped everyone would work in good faith.

“There are serious disagreements about both principles and policy and achieving real and meaningful legislation will require addressing the concerns and priorities of conservatives as well as liberals, Republicans as well as Democrats, the House as well as the Senate,” Hatch said. “If we have that perspective now and keep it with us as we move forward, I do believe that we can succeed.”

Carolyn Phenicie contributed to this report.