(CNN) -- A plan to overhaul the nation's immigration system crafted by a bipartisan group of senators gained the backing of Republican Sen. Kelly Ayotte Sunday, giving the bill a boost ahead of Senate debate this week.

The legislation, which emerged from the Senate "Gang of Eight," would create a pathway to citizenship for undocumented immigrants. The bill is far from certain to gain Senate approval, however, and Republicans in the House have already said the pathway to citizenship provision is a non-starter.

But Ayotte, who represents New Hampshire, said Sunday the bill deserves consideration as a fix to a system that is hurting American security and productivity.

"For too long, politicians on both sides of the aisle in Washington have failed to lead on this issue," Ayotte wrote. "And no doubt there will be naysayers in this debate who will continue to make excuses for inaction."

The Senate will hold procedural votes this week to begin debate on the immigration bill, which gained approval from the Senate Judiciary Committee in May. Lawmakers are expected to spend weeks weighing the bill, which has been endorsed by President Barack Obama and will be addressed by the president in a speech Tuesday.

If all 54 Democrat and Democrat-caucusing senators in the Senate support the bill, six Republicans will have to sign on for the measure to pass. Four Republicans helped draft the bill in the Gang of Eight - Sen. Marco Rubio of Florida, Sen. Lindsey Graham of South Carolina, and Sens. John McCain and Jeff Flake of Arizona - though Rubio has said he will not support the final product unless amendments are added increasing border security.

Rubio said last week the immigration plan does not yet have the support of 60 senators, but voiced confidence that eventually the bill would garner enough votes.

Ayotte defended the pathway to citizenship as a way to "bring undocumented people out of the shadows to separate those seeking economic opportunity from those seeking to harm us."

She also noted the bill's attempts to modernize the immigration system, saying in New Hampshire -- which does not house a large percentage of undocumented immigrants -- her constituents are concerned about outdated rules that cap the number of highly skilled immigrants coming to the United States.

"Moving to a more merit-based immigration system is good for our economy," she wrote. "By placing an emphasis on skills, we're harnessing the expertise and ingenuity of the most talented immigrants - especially those who have been educated in our colleges. They will put their energy and their ideas to work in our country - starting businesses and creating jobs for Americans."

Ayotte's endorsement, however, comes as Republicans continue to express opposition to the bill, and particularly its pathway to citizenship.. Speaking on "Fox News Sunday," Sen. Rand Paul said the bill doesn't solve any of the problems plaguing the current system, and stands no chance of passing the GOP-controlled House.

"I want to make the bill work, but see, the thing is, is what they have in the Senate has zero chance of passing in the House," said the Kentucky Republican. "So, why not come to a conservative like myself ... why not work with me to make the bill closer to what would be acceptable in the House?"

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