WASHINGTON (Reuters) - A sharply divided U.S. Senate on Thursday threw into doubt the fate of the plan backed by President George W. Bush to revamp U.S. immigration laws and left lawmakers scrambling to salvage the fragile deal.
The Senate fell 27 votes short of the 60 needed to limit the debate and advance the bill as amended toward a final vote, dealing a serious blow to the comprehensive effort to overhaul immigration law before Bush leaves office in January 2009.
The bill, which has drawn fire from both the right and the left, ties tough border security and workplace enforcement measures to a plan to legalize most of the 12 million illegal immigrants in the United States.
It also would create a temporary worker program and new merit-based system for future immigrants.
The showdown vote followed a series of amendments that began to unravel the fragile compromise painstakingly hammered out by a bipartisan group of senators and the White House. Backers said they would continue to work to patch up the bill.
Supporters worked throughout the day to stitch together an agreement that would allow the bill to advance.
Senate Majority Leader Harry Reid, a Nevada Democrat, said he would schedule a second vote on whether to proceed on Thursday night and warned if that also failed, the 100-member Senate would move on to other matters.
The first vote was 63-33 against advancing the bill.
Republicans said they needed more time to consider amendments to the complex and controversial legislation.
Democrats accused them of trying to kill the bill by prolonging debate and said Bush needs to get his fellow Republicans in line if he hopes to win the major legislative achievement during his final months in office.
"We have given the Republicans ample opportunity to offer amendments," said Senate Democratic Whip Richard Durbin of Illinois. Republicans said they would not be rushed.
"The majority is simply not going to get anywhere trying to stuff the minority and prevent the amendment process," said Senate Republican Leader Mitch McConnell of Kentucky.
Meanwhile, a public opinion poll by the Pew Research Center for the People and the Press showed Americans were ambivalent about the bill. The research group said most people surveyed supported its objectives, but about 41 percent of those who had heard about the legislation were against it.
The survey found that about 63 percent of those surveyed favored one of the bill's primary goals -- legalization of illegal immigrants if they pass a background check, work and pay fines. The poll of 1,503 adults was conducted May 30 to June 3, the research center said.
Conservatives argue the bill will give amnesty to people who broke U.S. laws, while unions say the temporary worker program would create an underclass of cheap laborers.
The compromise started to fray after the Senate voted late on Wednesday to terminate the guest-worker program after five years. The guest-worker program, which would allow workers to temporarily take jobs in the United States, is backed by business. Republicans said the amendment upset the compromise and wanted it changed.
(Additional reporting by Andy Sullivan)