Republican Sen. Kelly Ayotte on Sunday said she would support the bipartisan immigration overhaul under debate in the Senate and criticized "the broken immigration system we have now" as "unworthy of a great nation."

In a television interview and in a longer statement on her website, the New Hampshire senator became one of the first Republicans who didn't write the bill to line up behind the proposal that would offer a pathway to citizenship for the estimated 11 million immigrants living in the country illegally. Ayotte's support helps the bill's advocates move closer to the 60 votes needed to avoid a filibuster.

"The status quo isn't working. It's de facto amnesty. We need immigration reform that serves the best interests of our country," Ayotte wrote on her website.

A bipartisan group of eight senators — four Republicans and four Democrats — drafted the bill.

The Senate Judiciary Committee approved the measure last month with support from two of the Republican authors, along with Sen. Orrin Hatch. However, the Utah Republican says he will vote for the measure in the full Senate only if it includes higher penalties and delayed Social Security benefits for immigrants living illegally in the country.

Separately, Sen. Marco Rubio, R-Fla., said he will vote for the bill he helped write only with stronger border security than the bill already includes.

As drafted, the legislation also creates a low-skilled guest-worker program, expands the number of visas available for high-tech workers and de-emphasizes family ties in the system for legal immigration that has been in place for decades.

The legislation creates a 13-year route to citizenship for an estimated 11 million immigrants currently living in the United States illegally.

The bill is a "tough but fair way" for the estimated 11 million to come "out of the shadows" and "earn citizenship — go to the back of the line, pay taxes, pass a criminal background check, learn English," Ayottetold CBS' "Face the Nation."

It also sets border security goals that the government must meet before immigrants living in the U.S. illegally are granted any change in status.

"As a nation of immigrants, we must remember that we're all descended from people who came here from somewhere else in search of a better life," she said.

"But the broken immigration system we have now is unworthy of a great nation," she added. "It's time for Washington to tackle this problem head on."

Despite support from the White House, the AFL-CIO labor unions and the pro-business Chamber of Commerce, the bill's passage is by no means assured. Sixty votes are usually required to end Senate debate and consider adoption. There are currently 54 senators, including two independents, in the Democratic caucus, and 45 Republicans.

Leaders in the Democratic-led Senate want a final vote on the legislation by July 4.

The Republican-led House, meanwhile, is taking a smaller, piecemeal approach to the issue. Many of the components of the Senate bill are likely to find strong opposition there, giving House Republicans greater sway even before the Senate votes.

"What they have in the Senate has zero chance of passing in the House," said Sen. Rand Paul, R-Ky. "So, why not come to a conservative like myself and say, he's willing to work with you, why not work with me to make the bill closer to what would be acceptable in the House?"

Sen. Ron Johnson, R-Wis., said he remained hopeful a bill could be passed but said the bill would have to see changes if it stood any chance in the House.

"It doesn't do anybody any good just to pass in the Senate," Johnson said.

Immigration also has deep political implications.

Get the Monitor Stories you care about delivered to your inbox. By signing up, you agree to our Privacy Policy

In 2012, President Barack Obama won re-election with the backing of 71 percent of Hispanic voters and 73 percent of Asian voters. A thwarted immigration overhaul could send those voting blocs more solidly to Democrats' side in future elections. That has led some Republican lawmakers to support immigration reform, but the party's conservative base still opposes any legislation that would create a pathway to citizenship for immigrants living here illegally.

Paul and Johnson were on "Fox News Sunday."