* Republicans push for tougher provisions for those seeking legal status
* Immigrant advocates call proposals unworkable
* Key lawmaker says House could pass immigration bill by August
Health benefits and taxes for undocumented foreigners emerged on Tuesday as thorny issues in the U.S. immigration debate as the Senate prepared to consider changes to a sweeping bill next week.
A bipartisan group of senators are courting Republicans in hopes of reaching the minimum of 60 votes needed for passage. The centerpiece of the bill is a provision to grant legal status and a 13-year path to citizenship for the roughly 11 million undocumented immigrants, provided they pay fines totaling $2,000 and back taxes the government says they owe.
The legislation would also spend billions to bolster security along the southern border with Mexico. It would expand the number of visas available for high-skilled workers and create new visa programs for low-skilled workers such as janitors, construction workers and farm workers.
But some Republicans, including Senator Orrin Hatch of Utah, have indicated that the price of their vote might be tougher provisions for those seeking legal status. This poses a dilemma for the bipartisan Gang of Eight, which wrote the bill, and sought to achieve a balance between Democrats who want to ensure that the route to legalization is workable and Republicans who want to make sure that it is not overly lenient.
Hatch said his proposed changes to the bill would make it more "palatable" to those who object to its current form.
"This bill isn't going to pass without some of those amendments and some additional ones," he told reporters. "I want to get the bill so that it will pass so that it will have broad bipartisan support."
One of Hatch's amendments would require workers to show that they have paid taxes for all work they did from the time they entered the country.
The bill would allow undocumented immigrants to gain temporary legal status within six months. After 10 years, they would be eligible for permanent legal status and could gain citizenship after another three. Its current provisions would require that people applying for legal status pay any back taxes that the Internal Revenue Service, the tax-collection agency, says they owe.
BURDEN ON IMMIGRANT WORKER
Hatch's amendment would shift the burden for calculating back taxes from the IRS to the worker.
In the current bill, newly legalized immigrants would need to wait a minimum of 10 years to be eligible for federal subsidies to help them purchase health insurance under President Barack Obama's 2010 health law. One of Hatch's amendments would delay eligibility for another five years.
"You might as well not pass this bill," David Leopold, general counsel for the American Immigration Lawyers Association, said of Hatch's proposals.
He said the requirement on back taxes would prevent many people from gaining legal status. Calculating the taxes would be difficult because many employers would have little incentive to help workers compile their records.
"It cuts right into the whole purpose of this legalization program, and that's to give these people a tough but reasonable way to earn lawful permanent residency and compliance with the law," Leopold said.
At least one Republican author of the Senate bill, Senator Lindsey Graham of South Carolina, was sympathetic to that view.
"I want anybody that owes back taxes to pay them. But when you are talking about a system where a lot of people got paid under the table with cash, it could be problematic," Graham said. It could cost more to enforce such a law, he said, than it would generate in tax revenue.
But another Gang of Eight Republican, Senator John McCain of Arizona, said the back-taxes provision might not be too high a hurdle for those who want to become citizens. "I think it will be difficult and I think it should be difficult to become a citizen of the United States," he told reporters.
Graham said he did think there were the votes to pass the Senate bill. "Yeah, we have 60, I'm sure," he said.
Democratic leaders in the Senate are aiming to pass legislation before the July 4 holiday.
It is unclear when or whether the House of Representatives will introduce a comprehensive immigration bill. House Judiciary Committee Chairman Bob Goodlatte predicted that the lower chamber could pass immigration legislation by August but did not provide specifics on what kind of bill.
Goodlatte's committee, which oversees immigration, has avoided dealing with the 11 million illegal immigrants and is considering a series of individual bills to increase work visas and require employers to electronically verify the immigration status of potential employees.
The Senate and House must pass identical bills before President Barack Obama can sign one into law.