GWEN IFILL:The political push for overhauling the nation's immigration system gains new momentum.

REP. XAVIER BECERRA, D-Calif.: I suspect we're all here to send a very clear message: We are ready.

GWEN IFILL:California Democrat Xavier Becerra led other supporters of comprehensive immigration reform in a Capitol Hill rally today.

Inside the Capitol, a bipartisan group of eight senators put the finishing touches on legislation to overhaul the system expected to be unveiled tomorrow.

Florida Republican Marco Rubio, one of the members of the so-called gang of eight, described the plan Sunday on seven talk shows.

SEN. MARCO RUBIO, R-Fla.: I think it's important to understand it doesn't give anything. It allows people access to the legal immigration system.

Number two, some people won't qualify. They haven't been here long enough. They have committed very serious crimes. They won't be able to stay. Number three is, all people will get is the opportunity to apply for thing, to apply for a legal status, which isn't awarded on day one. I mean, there's a process for that.

GWEN IFILL:Although it has not been formerly introduced, it's been widely reported that the legislation would provide a pathway to citizenship for the estimated 11 million undocumented people now in the country and establish a 10-year process for obtaining a green card. Gaining full citizenship would take another three years.

Applicants would have to pay a fine and back taxes, learn English, and pass a criminal background check, among other hurdles. Rubio says that system would be triggered only if certain border security benchmarks are met.

MARCO RUBIO:That means securing the border, universal E-Verify and the universal entry-exit tracking system. If those three things are not in place, that green card process won't begin even if the 10 years has elapsed.

GWEN IFILL:But even with those assurances, some Republicans were skeptical, including Alabama Sen. Jeff Sessions.

SEN. JEFF SESSIONS, R-Ala.: No, I'm not convinced. I know Sen. Rubio's heart is exactly right. And I really respect the work of the gang of eight. But they have produced legislation, it appears, that will give amnesty now, legalize everyone that is here effectively today, and then there's a promise of enforcement in the future.

GWEN IFILL:White House Press Secretary Jay Carney said today the administration believes it's possible to satisfy concerns on both sides.

JAY CARNEY, White House Press Secretary: These are compatible ideas, enhancing border security, allowing for a clear path to citizenship that requires a number of very specific steps. So, the president is very pleased with the progress we have seen thus far.

GWEN IFILL:Once the bill is formerly rolled out tomorrow, the Senate Judiciary Committee will hold its first hearing later this week.

To help us sort through the next steps, we're joined by Brian Bennett. He covers immigration for the Los Angeles Times.

Brian, what was it that the bipartisan group has now agreed to and what are the issues that are still outstanding?

BRIAN BENNETT, Los Angeles Times: So, the bipartisan group plans to unveil their bill tomorrow, on Tuesday probably, maybe as soon as tomorrow.

And they have agreed on almost all the major points. They're still fine-tuning the bill today will unveil what they have decided on tomorrow. And so the main points are that there will be a legalization program for the 11 million people who are here without papers or who have overstayed their visas. And this program would start about six months after the bill is passed, after the Department of Homeland Security has outlined a way to secure the border.

And people will be able to apply, pay a fine, go through a criminal background check and apply to get legal status. And over the next 10 years, the U.S. would spend a lot of money on enhanced border security. And there would be a requirement that a certain certification was made on border security.

And, after that point, if those requirements were met on border security and a few other factors, then those people who were legalized would be eligible to apply for green cards and eventually become citizens.

GWEN IFILL:I want to circle back to some of the points you made. But let's start by talking about visas, this whole question of work visas.

Is that only for high-tech workers, or also for agricultural workers? That's been a sticking point along the way.

BRIAN BENNETT:This has.

So, one of the main things that the senators wanted to tackle in this bill was, how do you manage the future flow of immigrants so that you don't have as much pressure on the border of people wanting to come over illegally to find work? And so they have created a couple of work visa programs in the bill.

And one is for farmworkers. Over 50 percent of farmworkers in the United States came here illegally or overstayed their visas. And the bill would create a new visa system that would allow farmers to hire farmworkers from overseas.

Also, for the farmworkers who are already here, they would have a—if they stayed in agriculture work, they would have an expedited path to legal—to get a green card. And then when it comes to low-skilled workers, people like housekeepers, meat-packers, janitors, there's another new visa program that would be established as well to accommodate work shortages here in the United States.

GWEN IFILL:And that's different from the highly educated workers who the tech companies have been agitating to allow more of them in the country, right?

BRIAN BENNETT:And then there are also provisions in the bill to bring in more tech workers.

So, it would approximately double the number of slots that are currently available for high-skilled workers to try to satisfy the needs of Silicon Valley and other tech companies that want to hire more workers with advanced degrees.

GWEN IFILL:So, let's go back to the border security issue. That's been one thing that everybody, at least rhetorically, agrees about, that there ought to be, if not higher fences, at least higher enforcement along—tougher enforcement along the border.

Is that something which is now settled?

BRIAN BENNETT:It is essentially settled for this group of senators. We will see what happens when they roll it out to the other 92 senators in the Senate.

But this group of senators has decided that they have come up with a solution for border security and that they feel will help secure the border and prevent illegal immigrants from crossing in the coming years.

And what it essentially does is increases dramatically the amount of surveillance on the border and tries to get to a point where border security can respond to people crossing the border in a very quick way.

GWEN IFILL:Isn't there some disagreement at this point about how severe a problem it really is at this point?

BRIAN BENNETT:There is.

The White House and the Obama administration says that the border is more secure than it's been in 40 years and that spending more money on border security is not really necessary. And their also -- their follow-on point would be that by creating a legalization program and also by creating a way for people to come legally into the U.S. to work, that you take some of the pressure off the border.

And, you know, that said, there's been frustration among people who have seen these efforts go before without really trying to clamp down on the border and create a legalization program.

GWEN IFILL:And, Brian, what also feels different this time is we have gotten used to seeing rallies like the one we saw on Capitol Hill today with the same usual suspects saying it's time for immigration reform.

But it feels like this time like other people are on that bandwagon, including members of the larger faith community.

BRIAN BENNETT:The political environment is a lot different than it was, say, in 2007, the last time Congress took up an effort to overhaul the nation's immigration laws.

Right now, we have evangelical leaders who have signed on and said, look, there's a religious imperative to embrace the stranger and to reach out and help people who are in our community. And, on the Republican side, you have what they call a coalition of Bibles, badges and business. You have faith leaders. You also have law enforcement leaders, attorney general from the states, and other sheriffs, and business leaders who are saying, look, it's time to come—our system is broken. It's time to come and fix the system.

So, on the Republican side, they're getting pressure from some of these core constituents to come up with a solution.

GWEN IFILL:And is it fair to say, after seeing his kind of tour de force on the Sunday talk shows yesterday, that Sen. Marco Rubio, the Florida Republican, is the face of this? Or are there other—is there other agitation going on, especially over in the House?

BRIAN BENNETT:So, Marco Rubio is seen as essential to presenting this bill to conservative members of the Republican Caucus, because here's Marco Rubio. He was elected to his Senate seat in 2010 on a wave of Tea Party support.

And we will see if he's successful at trying to bring a lot of the conservatives in the Republican Caucus along board. There's a big hurdle in the House going forward. And the effort in the Senate is to try to get a bill passed with a lot of bipartisan votes to try to put pressure on the House to come up with either their own bill or to take up the Senate version.

GWEN IFILL:Which some members of the House are working on, I gather?

BRIAN BENNETT:That's right. So, there are about eight members of the House, four from each party, that have been working for several months on drafting their own legislation.

And that bill, they're going to take a look at what the Senate came up with, and they may present their own version of an immigration overhaul in the coming weeks.

GWEN IFILL:OK. Brian Bennett of the L.A. Times, we know you will be watching, and we will too.

BRIAN BENNETT:Happy to be on. Thanks.

GWEN IFILL:Online, we're kicking off a week of conversations on the evolving immigration debate. First up, Hari Sreenivasan talks to Shawn Moran of the National Border Patrol Council.