GWEN IFILL:And now to the first in a series of conversations about a key issue making its way through Congress. We're calling it “Inside Immigration Reform.”

The Senate Judiciary Committee took a big step last night toward providing a path to citizenship for 11 million undocumented immigrants living in the United States.

WOMAN:The votes are 13 yeas, five nays.

SEN. PATRICK LEAHY, D-Vt.: It passes.

GWEN IFILL:Three Republicans joined 10 Democrats to approve the measure and send it to the Senate floor by early June.

But before the vote, committee Democrats were forced to back away from a provision that would have specifically included protection for same-sex immigrant couples.

For more on the tradeoffs that led to the committee vote, I'm joined by Alan Gomez, who covers the issue for USA Today.

Welcome, Alan.

So the—this big vote came this close to not happening. It could have easily been derailed.

ALAN GOMEZ, USA Today: Yes.

Sen. Leahy, chairman of the committee, introduced very briefly this amendment that would have extended those rights to same-sex couples. Basically, if you're a U.S. citizen and you have a permanent partner overseas or somebody who is here who is undocumented or on a temporary visa, you would be allowed to petition for them, just as other couples can in this country.

He introduced it. He allowed people to debate it. A lot of Democrats on the committee supported it, said how much they wanted to do it. It was a very emotional hearing, a very—in a hearing filled with so much detail and policy, it was a very emotional moment where they were able to express their support for this. But they all urged Leahy to back off and to not request a vote on the amendment. They worried it would sink the whole bill.

GWEN IFILL:Because there were Republicans especially on the committee who had said, I won't—I will just walk away from the whole deal if that's part of the compromise at the end.

ALAN GOMEZ:Exactly. This bill was ...

GWEN IFILL:Who were they?

ALAN GOMEZ:This bill was written by—it's called the gang of eight, eight senators, bipartisan senators, but Sen. Graham specifically is one of the members of that group who wrote the bill and sits on the committee, and said yesterday—he basically said, if you pass this, this thing falls apart because this group falls apart.

GWEN IFILL:That was Sen. Lindsey Graham of South Carolina.

ALAN GOMEZ:Yes.

GWEN IFILL:So, what was the reaction from the LGBT community to this, who had been pushing so hard and as you point out so emotionally for this to be included?

ALAN GOMEZ:This was a big, big blow.

I don't think anybody in that community expects this provision to suddenly appear in the House of Representatives. It's Republican-led. It's very conservative. They're aware of the fact they don't have much of a shot over there.

So, at this point, all they got is amending on the Senate floor—to get this on the Senate floor, and that's a much more difficult thing to do. This was a Democratic-led committee. They thought they had the votes. They were lobbying very hard in this case, the Democrats on the committee, to hold firm and to get it onto the bill. They didn't really bother trying to lobby the Republican members of the committee, assuming that they weren't going to swing them over on such a tough issue.

And, obviously, it didn't work out for them.

GWEN IFILL:Sausage making is sometimes the most fascinating and the most frustrating part of the legislative process. What else was included or excluded in the process as they were getting to this committee vote?

ALAN GOMEZ:It's really been —they had five hearings and they heard over 200 amendments.

And you—I could bore you for quite a while discussing what they got into, but some of the things that they really addressed and that are clear that are going to continue to be issues in this deal with border security. Conservative Republicans, they really want, need for this bill to ensure that it's going to finally secure the border and we're not going to get another wave of illegal immigrants coming into the country.

So, what they were able to do is get some steps. They were able to—the original bill required for 100 percent of the border to be monitored by Border Patrol, and 90 percent of people trying to cross over to be turned back. But the original bill only asked for that in three sectors along the border, these high-risk, high-volume areas.

Chuck Grassley, senator from Iowa, was able to extend that for the entire border.

GWEN IFILL:But there were also questions about who gets to come in, not only gays and lesbians, but also what kind of workers get to come in.

ALAN GOMEZ:Yes, absolutely.

One of the thing that this bill is expands the legal immigration system. Part of the reason that we have so many undocumented immigrants in the country is that the legal immigration system, that's the one thing everybody agrees on, is broken. So, they're bringing in more high-tech visas, more computer engineers, more people who work in those fields.

But it also creates a visa for low-skilled workers who work in restaurants, who work in the retail industry. And that's where we have seen a lot people come in. It provides these avenues hopefully to get the workers that U.S. businesses need so that that magnet of jobs isn't there for them to try to come in the future.

GWEN IFILL:We just saw the video of the celebration that went on in the Senate hearing room, which is kind of unusual after a mere committee vote.

ALAN GOMEZ:Yes.

GWEN IFILL:But there are a lot of pressure points coming on the Senate and the House from all kinds of external places. Who are those people who are in there who are lobbying, who are pressuring to get things in or out of this kind of legislation?

ALAN GOMEZ:And you're absolutely right.

First off, the—I don't know if Sen. Leahy has had his name chanted like that in quite a bit after the hearing once it was passed. But there are—there remain many points where this thing can fall apart. One example, Orrin Hatch, senator from Utah, it was very important to get his vote and they worked out a compromise for these high-skilled workers to come in, made it a little bit easier for U.S. businesses to hire those foreign workers, but at the same time that really upset labor unions in the country.

So, the AFL-CIO responded very angrily to that amendment. They still support the bill, and they're still saying, OK, it's all right, let's move forward with this, but those are the kinds of things that we will be looking for in the weeks ahead.

GWEN IFILL:And, briefly, what was the White House's role in all of this? They certainly were pushing for —for instance, for the gay and lesbian portion.

ALAN GOMEZ:They were pushing very hard for the gay and lesbian amendment.

There was an AP report that the White House asked Leahy not to introduce it. The White House, Jay Carney today said he didn't—he's not aware of that conversation taking place. Leahy's office says they don't talk about the private discussions that they have. And the White House is fighting back on that.

But they—you know, he's made very clear that he supports the amendment. As far as the politics of whether he got in there and asked for him to pull it back, we're not sure.

GWEN IFILL:Many steps to go. It's first to the full Senate, then to the House. And so we will be talking about this a lot.

Thank you very much, Alan Gomez of USA Today.

ALAN GOMEZ:Thank you.

GWEN IFILL:We will have more on the emerging legislation in coming days.

And on our website, we take a look at a virtual march being launched online in support of the immigration law. That's at NewsHour.PBS.org.