The US Senate took a bipartisan vote to end debate on a sweeping but contentious immigration bill on Thursday, paving the way for its final passage in the upper chamber.
Fourteen Republicans joined a unanimous Democratic side in voting to end debate on the most comprehensive immigration reform effort in a quarter century, with a final vote slated for 4:00 pm (2000 GMT).
The bill would provide a 13-year pathway to citizenship for more than 11 million undocumented people in the country, revamp the legal immigration system and devote billions of dollars to enhanced security along the border with Mexico.
"We are moving one step closer to fixing our broken immigration system," Republican Senator Jeff Flake of Arizona, one of the authors of the bill, said shortly after lawmakers voted 68-32 to invoke cloture on the far-reaching legislation.
The four Democrats and four Republicans known as the "Gang of Eight" spent months crafting the huge document, which pours $46 billion into border security and other efforts, including electronic employment verification and a modernized entry-exit system.
The bill, supported by President Barack Obama, was debated for three weeks on the Senate floor and dozens of amendments were added as Republicans squared off against one another over the merits of the legislation.
"It's been a very tough negotiation," Democratic Senator Mary Landrieu acknowledged. "It's not perfect, but it's balanced."
With the bill expected to pass by a similar margin later in the day, it would then head to the House of Representatives, where its fate is far less certain.
Obama has said he hopes to sign immigration reform into law this year, but several House Republicans have said the bill would be dead in the water without significant changes, particularly on border security.
"The House is not going to take up and vote on whatever the Senate passes," Republican House Speaker John Boehner told reporters.
"We're going to do our own bill, through regular order, and it'll be legislation that reflects the will of our majority and the will of the American people," he said.
"Listen, immigration reform has to be grounded in real border security. That's what the American people believe, and it's a principle that our majority believes in as well."
The Senate bill would more than double the border patrol by adding 20,000 new agents and double the length of security fencing to 700 miles (1,120 kilometers) along the 2,000-mile border with Mexico.
Democratic Senator Robert Menendez, one of the "Gang of Eight" who crafted the legislation, pointed to the stiff requirements for those who would pursue citizenship.
"They'll have to pass background checks, pay a fine, pay their taxes, but if they do, there will be no obstacle they cannot overcome to the day when they raise their right hand and take their naturalization oath," he said.
"Too many families have waited too long for that day."