WASHINGTON - Shortly after the November election, Democratic Sen. Chuck Schumer of New York approached Republican Sen. Marco Rubio of Florida about joining a bipartisan effort to overhaul the country's immigration system.
The two weren't particularly close. In fact, the liberal Schumer led Democratic efforts in 2010 to defeat Republican Senate candidates, including Rubio, a conservative.
But Schumer viewed the Cuban-American senator from West Miami as a natural fit for the immigration overhaul because of his Hispanic heritage, his high standing among Tea Party activists and his advocacy for moderate immigration policy.
Rubio had a stake in the issue as well. Last year, he proposed his own changes, and a major legislative victory on immigration could boost any ambitions he might have to run for president in 2016.
On Jan. 28, Schumer and Rubio stood together at a news conference and pitched a plan to provide some of the 11 million illegal immigrants a path to citizenship contingent on tougher border security measures.
Many hurdles remain, but lawmakers and immigration advocates say the momentum to overhaul the system is the strongest it's been in a generation, thanks in part to the broad bipartisan coalition behind it.
Republican Sen. John McCain of Arizona and Democrat Sen. Dick Durbin of Illinois, who have pushed immigration measures in the past, laud Rubio for trying to win over conservatives who traditionally reject any proposal to give illegal immigrants a route to legal status.
Rubio has wooed TheWall Street Journal's editorial page writers and has made the rounds on right-wing talk shows to convince Rush Limbaugh, Sean Hannity and others that the immigration plan is worth considering.
Mostly, he's gotten a respectful hearing and expressions of willingness from skeptics to consider what Rubio calls "the reality of the situation."
"He's been Daniel in the lion's den," Schumer said Wednesday, citing Rubio's appearance on Limbaugh's program. "It was amazing. When the show started, Limbaugh was far more hostile (to the idea) than at the end. (Rubio's advocacy) is going to be a real service."
The bipartisan plan, introduced by four Democrats and four Republicans, would create a path to citizenship for "unauthorized immigrants" who pass a criminal background check, pay back taxes and learn English among other requirements, according to an outline of the proposal.
They would gain immediate legal status by registering with the government while waiting, perhaps a decade or longer, to earn a green card. They would not face deportation. But they would be at the back of the citizenship line behind immigrants in the country legally.
The proposal also would require extra border security, such as unmanned aerial drones and increased border patrols. It would crack down on employers who hire illegal immigrants. And it would require completion of an "entry-exit system" to closely track people arriving in the U.S. on temporary visas, a measure Rubio has pushed.
An estimated 40% of illegal immigrants entered the country on a visa that has since expired.
"There are 11 million human beings in this country that are undocumented," Rubio said at the news conference last Monday. "That's not something that anyone is happy about. That's not something anybody wanted to see happen, but that is what happened. And we have an obligation and the need to address the reality of the situation that we face."
One reality is that Hispanic voters are much more likely to back Democrats for national office. Republican presidential nominee Mitt Romney received only 27% of the Latino vote in November, a point McCain alluded to during the news conference.
"The Republican Party is losing the support of our Hispanic citizens," said McCain, who won 31% of the Hispanic vote when he ran for president in 2008. "And we realize that there are many issues on which we think we are in agreement with our Hispanic citizens, but this is a pre-eminent issue with those citizens."
Rubio, whom Romney considered selecting as a running mate last year, has chided Republicans for using harsh, anti-immigration rhetoric.
Last year, he talked up the idea of letting the children of illegal immigrants stay in the U.S., provided they complete high school and have no criminal history. The bill, a version of the DREAM Act, was never introduced.
Under the latest plan, those children might have a faster path to citizenship than other illegal immigrants - and perhaps those already in line - a compromise Rubio agreed to in concept as part of the comprehensive package.
In the past, Rubio has opposed the idea of trying to deport all illegal immigrants, but this is the first time he has pushed to give every qualified illegal immigrant a chance to become a citizen.
Ali Noorani, executive director for the National Immigration Forum, which supports the path to citizenship, said Rubio is not the only conservative backing the concept.
"If you look across the country, there is incredible energy on this issue, from socially conservative evangelicals, from Republican law enforcement officials, from conservative business owners," he said. "Rubio's not out there on a limb. Rather, he's leading a charge of conservatives who want to engage conservatives."
But some on the right are chilly to the new bipartisan immigration proposal.
Sen. David Vitter, R-La., called Rubio "amazingly naive" for thinking the proposal's security measures would precede what Vitter and other critics of the plan call its "amnesty" provisions.
Mark Krikorian, executive director of the Center for Immigration Studies, which advocates tougher enforcement of immigration laws, said conservatives are likely to balk at the idea once they see the fine print - even if Rubio's the one selling it.
"A lot of people are going to take his word for it initially," he said of the senator. "But once there's actual things in black and white and people start taking them apart and analyzing what they mean, that deference toward him is going to evaporate very quickly."
Krikorian said he wouldn't be surprised if Rubio eventually withdraws his support from the measure once he realizes conservatives would punish him for it if he runs for president in 2016.
"I think if he pulls out at some point, he might have enough credibility with conservatives that his pulling out can give him cover and atone for the rest of it," Krikorian said. "If he sticks with it and it passes or sticks with it and it fails, it could hurt him significantly."
Ledyard King, Gannett Washington Bureau