By Thomas Ferraro and Richard Cowan
WASHINGTON (Reuters) - A landmark immigration bill survived a major challenge in the Senate on Thursday when its bipartisan "Gang of Eight" sponsors beat back an amendment that would have delayed a pathway to citizenship for 11 million illegal residents.
The proposal by Iowa Republican Charles Grassley would have prohibited a first step toward granting them legal status until the U.S. Department of Homeland Security "has maintained effective control" of the entire U.S.-Mexico border - 1,969 miles - for a period of six months.
Critics charged it could take years to achieve such a nebulous goal, undermining a centerpiece of the effort to overhaul the immigration system.
The Senate bill would allow those living in the United States illegally to apply for legal status within six months of enactment.
The vote on the Grassley amendment was the first test of unity and clout in the full Senate for the Gang of Eight - four Democrats and four Republicans - as they protected what they see as a pillar of their measure: a provision to quickly make undocumented immigrants legal residents.
Grassley said the defeat of his amendment, 57-43, broke a promise by President Barack Obama's Democrats to permit an "open debate." Democrats forced a vote after little discussion.
"This type of obstruction is the wrong way to start the amendment process," said Grassley, who argued his amendment would ensure there is "true border security before legalization and that's what the people of this country want."
Republicans in the House of Representatives touted a tough new law-and-order bill aimed at illegal immigrants. It was a sign that at least for now, the conservative wing of the party was driving the immigration debate in that chamber.
House Judiciary Committee Chairman Bob Goodlatte called the legislation "game changing" with its provisions giving state and local police departments powers to apprehend undocumented people.
Democrats characterized the bill as a step backward that would lead to racial profiling by local police.
"It's alarming that this bill would turn millions of undocumented immigrants into criminals overnight. It's not only terrible politics but its inhumane policy," said Representative John Conyers of Michigan, the senior Democrat on the committee.
Also on Thursday, five Senate Democrats met with Obama to discuss strategy, including how to meet Republican demands to bolster border security. Afterward, one aide said the president and senators "discussed a path forward in the Senate and strategy for the next two weeks."
The five include the four Democrats in the Gang of Eight - Dick Durbin of Illinois, Charles Schumer of New York, Robert Menendez of New Jersey and Michael Bennet of Colorado.
Senate Judiciary Committee Chairman Patrick Leahy, who shepherded the bill through his panel last month and is now charged with getting it through the full Senate, also attended. Following the meeting, Leahy predicted the measure would pass the Senate before July 4.
"90 PERCENT CONTROL"
Separately, another group of senators quietly sought to negotiate a deal to toughen border security without offending the coalition of senators now supporting the bill.
Arizona Republican Senator John McCain, who is part of the Group of Eight, told Reuters he was uncertain if progress had been made.
"We have to get a certain number of people that would agree to a plan that we could achieve 90 percent effective control of the border," McCain said. "We think it's possible but I'm not predicting. Technology is one of the ways we get there."
Assistant Senate Republican Leader John Cornyn of Texas, who has an amendment of his own that seeks 90 percent "effective border control" before any legalization of undocumented workers, said he had seen no progress in finding a compromise.
But Cornyn added, "I'm happy to listen and in the process, talk to my colleagues."
Backers of the nearly 900-page bill are aiming for a vote on passage by the end of this month, confident it will prevail. The Republican-led House of Representatives is expected to produce different legislation in coming weeks, which would have to be reconciled with anything the Senate passes.
Polls show public support for the Senate bill, including the pathway to U.S. citizenship. Debate on the legislation is expected to last the rest of the month
(Editing by Peter Cooney)