Congress is closer than it has been in decades to crafting a comprehensive immigration reform bill, but lawmakers are far from an agreement on legislation that can pass both the House and Senate.

Democratic senators last week could barely contain their excitement over the progress made by a bipartisan coalition of eight senators writing an immigration reform plan.

"We are real close, for the first time, to coming up with a bipartisan agreement that has a darn good chance of becoming law," said Sen. Charles Schumer, D-N.Y.

But there are dozens of Republicans who oppose the legislation on which the bipartisan group is working because it would provide legal status to 11 million immigrants already living illegally in the U.S., making them eligible for government benefits like Medicare and food stamps.

"We can't afford it," Rep. Paul Broun, R-Ga., said recently on the Laura Ingraham radio program. "The federal government is broke."

But big losses among Hispanic voters in the November election have pushed Republicans -- led by Sens. Marco Rubio, R-Fla., and Rand Paul of Kentucky -- to soften their anti-immigration stance.

The Senate's "gang of eight" proposal would create a 13-year "path to citizenship" for illegal immigrants, but only after the U.S.-Mexico border is secured, according to those familiar with the plan. It also would create a guest worker program and a program to increase the number of work visas for foreigners.

Schumer said the group will reveal its proposal in April. Senate Democrats want to start debate on the compromise by early summer.

There are Republicans in both the House and Senate, however, who are far less enthusiastic about the prospects of any compromise that provides a path to citizenship, which they derided as amnesty for lawbreakers.

The House is writing its own legislation, which may not be ready until later this year, and some Republicans, including Rep. Raul Labrador of Idaho, are already lining up in opposition to a citizenship provision.

And opposition could grow depending on what a pair of studies being released next month say about the cost of comprehensive reform and its impact on U.S. wages.

One study, by the conservative Heritage Foundation, will show that legalization could open up entitlement benefits and access to health care to millions of people, at tremendous expense to the federal government. A second study, by Harvard University, will show that legalization could reduce the wages of lower-income workers.

The cost factor may make it hard for fiscally conservative House Republicans to vote for a bill that includes either legalization or a path to citizenship.

"They are not going to be able to figure out a way to keep it from absolutely busting the budget," a person familiar with the Heritage study told The Washington Examiner.

Six Republican senators, meanwhile, wrote to Senate Judiciary Committee Chairman Patrick Leahy, D-Vt., asking for additional time to "read and analyze" the compromise before it is pushed through the panel.

Haley Barbour, the former Mississippi governor heading a Bipartisan Policy Center immigration task force, told reporters last week that immigration reform is "complex and contentious" and could take a long time to complete.

"It's a little bit overly optimistic to talk about what we're going to get done this spring or before the August recess," Barbour said.