A bipartisan coalition of senators on Monday unveiled a "tough but fair" immigration reform blueprint that would provide instant legal status to 11 million immigrants already living illegally in the U.S. and, eventually, provide them with a path to citizenship.

"Immediately when the bill passes, people who are here living in the shadows would get a legal right to stay here and work," said Sen. Charles Schumer, D-N.Y., one of the bill's co-sponsors. "They would no longer be deported, provided they don't have a criminal record."

The blueprint also calls for tighter boarder security, more guest-worker permits, changes in the legal immigration system and a verification process for employers hiring immigrants. Immigrants would not be eligible for green cards until new border security measures are in place.

Lawmakers said the bipartisan package represents their best opportunity yet to revamp the nation's immigration laws after five years of false starts and partisan bickering.

Immigration reform has been languishing on Capitol Hill since former President George W. Bush first proposed comprehensive changes in 2007, only to be shut down by fellow Republicans who charged that any pathway to citizenship for illegal immigrants amounted to "amnesty" for lawbreakers.

But Republicans now appear more inclined than ever to join the reform effort, lawmakers acknowledge, after taking a beating among Hispanic voters in last year's election, when President Obama won 71 percent of Latino voters and Republican Mitt Romney got just 27 percent.

"The Republican Party is losing the support of our Hispanic citizens," said Sen. John McCain, R-Ariz., a longtime supporter of immigration reform and a co-sponsor of the reform package. "And we realize that there are many issues in which we think we are in agreement with our Hispanic citizens, but this is a pre-eminent issue with those citizens."

Still, the package faces opposition from Republicans, who are sure to seek greater emphasis on border security, just one of four areas the package addresses.

Senators revealed their proposal one day before President Obama was set to unveil his own immigration reform plan in Las Vegas. White House spokesman Jay Carney called the Senate proposal "a big deal" and said it "mirrors" the president's own plan.

The group backing the bipartisan plan includes a number of senior lawmakers, like McCain, who have been working on the immigration issues for years. But it also includes Sen. Marco Rubio, R-Fla., a Cuban immigrant and rising star in the Republican Party who insists that the GOP must win over Hispanics, the nation's fastest-growing voting bloc.

"The issue of immigration is not a simple one," Rubio said, "but I think we have the opportunity to do it right."

Rubio and other co-sponsors heralded the bipartisan blueprint with optimism despite repeated failures in Congress to pass immigration reform.

"We've been down this road before," said Sen. Dick Durbin, D-Ill. "But I feel very good about our chances this time."

Lawmakers hope to pass the reform bill by late spring or summer.

But some Republicans on Monday warned against a comprehensive deal that does not curb the influx of illegal immigrants. They cited the 1986 reforms signed by then-President Reagan, which did little to secure the border and created a sharp rise in illegal immigration.

"This promise of enforcement, as long as we have amnesty, is a recipe for failure," said Sen. David Vitter, R-La.