Immigration bill expected to overcome early hurdles in the Senate

The Senate is expected to proceed toward a bill that would overhaul the nation's immigration system Tuesday, overcoming an early hurdle for what is expected to be a monthslong process.

The chamber will take up a procedural vote that allows senators to begin voting on amendments to the immigration bill, crafted by the bipartisan Gang of Eight and passed by the Senate Judiciary Committee. Senate Republican leaders have signaled that they will join Democrats in supporting the motion.

This initial Republican nod of approval, however, does not mean GOP lawmakers will vote for final passage. Over the coming weeks, Republicans and Democrats will propose their own changes to the bill. Many Republicans, including the bill's co-author, Florida Sen. Marco Rubio, have said they will reject final passage unless the chamber agrees to amendments that strengthen border security.

Speaking on the Senate floor Tuesday morning, Senate Minority Leader Mitch McConnell, who plans to support Tuesday's motion to proceed to the bill, said he would withhold judgement on whether to support the bill's final passage until after the amendment process.

"It’s time for the Gang of 100 to do its work — for the entire Senate to have its say on this issue, and see if we can do something to improve the status quo," McConnell said. "At the risk of stating the obvious, this bill has serious flaws. I’ll vote to debate it and for the opportunity to amend it, but in the days ahead there will need to be major changes to this bill if it’s going to become law. These include, but are not limited to, the areas of border security, government benefits and taxes."

The amendment process begins one of the most contentious periods for the bill in the Senate. Republican opponents of the overhaul are expected to offer a series of amendments that could derail the effort. Likewise, Democrats will be required to support changes that strengthen enforcement or face defections from key Republicans who have worked on the bill from the beginning.

In the House, a bipartisan group of lawmakers is working on its own version of an immigration reform package. House Speaker John Boehner has urged committees to wrap up their work on the bill by the Fourth of July recess. Boehner said in an interview Tuesday with ABC News that there is "no question" the bill could pass by the end of the year.