
The bill includes plans to spend more than 40 billion U.S. dollars to beef up the U.S.-Mexico border with thousands of additional law enforcement personnel. It also provides a 13-year path to citizenship for roughly 11 million illegal immigrants, whereby they would pay fines and back taxes before becoming eligible for legal status.
Brookings Institution Senior Fellow Darrell West told Xinhua that House Speaker John Boehner does not control his Republican caucus. He noted that many Republicans oppose the bill, including the pathway to citizenship for illegal immigrants.
Another major disagreement among Republicans is border security. Republican opponents of the bill argue that securing the border will take time, if not years, and contend that border security must happen before undocumented workers are provided a path to citizenship.
But the bill's GOP supporters contend that the legislation's provision to provide an additional 20,000 border agents will significantly ratchet up border security.
Republican Senator John McCain has come out strongly in favor of the bill. He told CNN's "New Day" program on Tuesday that the legislation would "militarize" the U.S.-Mexico border.
The statement came on the heels of comments by Senator Rand Paul, a member of the Tea Party movement, who said Sunday that the bill was "dead on arrival" in the House, arguing that border security must precede immigration reform.
Critics also said allowing a path to citizenship would lower wages for the lower middle class and working class, as unskilled, new immigrants from developing countries are more likely to accept lower wages. Others dismiss that argument, countering there will be little impact on wages.
Former GOP vice presidential nominee Paul Ryan on Tuesday told CBS' "This Morning" that the bill's provisions, which toughen border security with new agents and billions of dollars worth of high tech equipment including infrared cameras, "obviously makes final legislation more likely."
In sharp contrast to Republicans, Democrats have remained unified on the bill, with President Barack Obama touting the legislation as key to ensuring continued success for the world's largest economy.
The bill is expected to sail through the Senate this week, but will have a tougher time getting through he House, experts said.
Some senators, however, questioned the urgency of passing the bill so soon. Senator Paul said Wednesday that he would have liked to introduce an amendment that would prohibit undocumented workers from receiving welfare payments. He questioned Congress' need to push the bill through the Senate this week.