In the first legislative test for the U.S. Senate’s bipartisan immigration bill, the Judiciary Committee rejected a Republican attempt to significantly delay the legalization process for 11 million undocumented immigrants, a central focus of the bill.

Only the two Republican co-authors of the bill, Senators Jeff Flake of Arizona and Lindsey Graham of South Carolina, voted with the panel’s Democrats to defeat the Republican plan on a 12-6 vote.

The vote, which was not a surprise, came in the first hours of the first day of what is expected to be a weeks-long effort to agree on a comprehensive immigration bill that would be sent to the full Senate. The committee’s 10 Democrats and eight Republicans were prepared to argue over as many as 300 amendments to the overhaul of U.S. immigration laws crafted by the bipartisan “Gang of 8” senators.

Some of the proposed amendments are designed to appeal to the Democratic majority as ways to improve the measure, while others are seen as ways to possibly kill it. Four of the senators who crafted the complex measure are on the committee, and these two Democrats and two Republicans have agreed to jointly oppose any amendment seen as a “poison pill.”

The day began with a warning from the panel’s top Republican that he would make the process as long and “arduous” as possible.

“I plan to ask many questions throughout this process,” Iowa Senator Charles Grassley warned. “I want to know how the bill doesn’t repeat the mistakes of the past.” Grassley, in a statement, promised an “arduous” and “robust” debate.

Grassley followed up with an amendment to require that the Obama administration achieve full control against illegal immigration of every part of the U.S. border before any of the undocumented people currently in the United States could be considered for legal status.

As currently written, the legislation would begin the legalization process almost immediately after enactment, while the administration simultaneously begins a new border security program.

“This amendment would set a standard that would basically delay probably forever” the legalization of the 11 million, argued Democratic Senator Charles Schumer of New York, one of the Gang of 8.

This early test vote will not end what is expected to be a tense argument over the next several weeks over whether the southwestern U.S. border is adequately secured and whether illegal immigrants, many with deep roots in the United States, should be rewarded with a pathway to citizenship.

The kickoff of Senate Judiciary Committee debate on the bill came as a new Pew Research Center poll found that 75 percent of Americans believe that immigration policy needs major changes and 73 percent say there should be a way for illegal immigrants to stay in the United States.

But less than half, 44 percent, said they favored allowing undocumented residents to apply for citizenship.

The opening day of the debate reflected both the deep divisions and high hopes surrounding a measure that would put 11 million illegal residents on a path to citizenship and totally revamp the criteria for who gets into the United States and for what purpose.

Before the session began, a group of spectators with the words “Campaign for Citizenship” emblazoned across their white T-shirts stood in a circle in the hearing room, their hands raised above their heads, for a silent prayer.

The Rev. Alvin Herring of Washington, D.C., told Reuters: “It’s going to take prayer and it’s going to take us acting on our prayers” in order to get immigration legislation enacted.

Despite those prayers, senators quickly got into some heated exchanges.

Republican Senator Jeff Sessions of Alabama, a vigorous opponent of the bill, contended it would bring 30 million new immigrants into the United States over the next 10 years, costing Americans jobs and hurting the U.S. economy.

Schumer rejected that claim and invoking a phrase that haunted Republican presidential nominee Mitt Romney last year, asked, “Do you believe they should all be self-deported?” Romney had suggested that life for the 11 million should be made so uncomfortable that they would simply “self-deport.”

The stance was seen contributing to Hispanic voters’ overwhelming rejection of Republican candidates in 2012 elections.

At another stage in the debate, Graham caused a stir in the room when he said that immigrants cross the southwestern border with Mexico because they “live in hell holes and they want to live here.”

Graham was making the argument that more border fencing will not deter them while the bill’s move to improve foreigners’ legal access to jobs would help fix security problems.

During a break, Schumer told reporters that he worries “all the time” about a Democratic amendment Judiciary Committee Chairman Patrick Leahy has offered that would cover same sex couples in the bill’s new immigration reform policies. He said the Gang of 8 was evenly split over that amendment.

The panel’s work could stretch through May, and if it agrees on legislation, the full Senate is likely to debate it throughout June.

But several Republicans on the committee – and in the full Senate – are skeptical of legalizing the millions of people who either came into the United States illegally over the past 27 years or overstayed their visas.

Instead, they want a more limited immigration bill that mostly concentrates on other aspects of the legislation, including further securing U.S. borders and creating more visas for skilled workers to help American high-tech companies.

Meanwhile, negotiations on a bill in the more conservative Republican-led House of Representatives slogged on.

According to one House source familiar with the negotiations, disagreements remained over several important policy matters, including how many low-skilled workers should be allowed into the United States for jobs ranging from cooks and hotel maids to construction workers.

This was one of the most contentious issues during negotiations between the AFL-CIO labor organization and the U.S. Chamber of Commerce in the run-up to introduction of the Senate bill.

Marshall Fitz, an immigration specialist at the Democratic-leaning Center for American Progress, said that besides policy disagreements, House members also face many political and strategic questions.

There is widespread belief that for a bill to pass the House, it will have to be significantly more conservative than the Senate bill, which some immigration advocacy groups already complain contains overly rigorous requirements.

“Democrats in the (House) group are rightly wary of signing onto a bill that is significantly to the right of what the Senate is doing,” Fitz said.

-Reuters