WASHINGTON – Newt Gingrich's push for a "humane" immigration policy has pinched a nerve for many conservatives and prompted criticism from rival Republican presidential campaigns who are invoking the loaded descriptor: "amnesty."

Gingrich, meanwhile, is sticking to his plan to create a path to legal status for illegal immigrants who have been in the United States for a long time and have ties in the community as a practical solution to an intractable mess.

The former Georgia U.S. representative and presidential hopeful got into an extended sparring match with his Republican rivals in Tuesday night’s debate on the emotional topic, and it became the debate’s most talked-about moment.

“Politicians are very much lining themselves up so they don’t alienate Latino voters, and the only reason Newt did that … is he wants the Hispanic voters,” said Bill Evelyn, the founder of the State of Georgia Tea Party group. “Newt is actually not well liked in the tea party for reasons above and beyond that, but it will hurt him with the tea parties. It absolutely will.”

Phil Kent, a member of Georgia’s immigration control board and national spokesman for Americans for Immigration Control, was willing to cut Gingrich some slack.

“Remember that Gingrich retains strong credentials on this issue since he favors enhanced Mexican border security and fencing, no benefits for illegals, tough employer sanctions if illegals are knowingly hired, and making English our official language of government,” Kent wrote in an email. “So his latest stance shouldn’t hurt his candidacy too much. Yet he runs the risk, with more such thinking exercises, of letting Mitt Romney flank him on the right regarding this issue.”

Gingrich has risen to the top of the polls recently on the strength of his debate performances and the shortcomings of other candidates, becoming the latest in a carousel of top challengers to front-runner Romney, the former governor of Massachusetts.

Rival campaigns pounced on the immigration issue as a chance to take Gingrich down a peg.

“I think there’s a major and legitimate difference of opinion on immigration between Newt Gingrich and Mitt Romney,” said Romney adviser Eric Fehrnstrom. “Newt Gingrich supported the 1986 amnesty and even though he concedes it was a mistake, he’s willing to repeat that mistake by granting amnesty to today’s illegal immigrants.”

Minnesota Rep. Michele Bachmann, who has faded from the campaign’s forefront after a fast start, also labeled Gingrich’s plan as amnesty during the debate.

“I think he’s wrong on the issue, so yeah, clearly that’s a vulnerability,” said Bachmann spokeswoman Alice Stewart. “And it was an opportunity to show where they contrast on that issue.”

Gingrich spokesman R.C. Hammond wrote in an email that “People understand what Newt is proposing, it’s the politicians who are having trouble.”

To underscore the point, the Gingrich campaign detailed its policy in a 2,800-word post on its website Wednesday.

Gingrich has dealt with immigration policy for decades, including the 1986 law, which he acknowledged during the debate fell short on border security and a guest worker program.

A key component of Gingrich’s plan involves easy-to-obtain and privately administered legal status for immigrants who can get jobs. It’s known as the “red card” proposal from conservative Denver billionaire Helen Krieble, whom Gingrich cites as an influence in his 2009 book “Real Change.”

Immigrants and their families would get the biometric cards for legal status, but not citizenship. Companies would bring in the migrants via foreign-based employment agencies, which would conduct background checks on applicants. There would be no limit or quota other than market conditions. U.S. tax and labor law would apply to the migrant workers, and their Social Security taxes would be routed back to the states to pay for social services.

For those who already are here illegally, Gingrich proposes a path to legal status to be determined by a citizens’ review board based on criteria including length of time in the United States, family and community ties, ability to support oneself without entitlement programs and proficiency in English.

Some immigration hawks see the stance as conflicting with key principles.

“It feeds into a narrative that a lot of conservatives have about Gingrich which is he isn’t really all that conservative,” said Mark Krikorian, executive director of the Washington-based Center for Immigration Studies.

This could be “the point where he peaks and starts fading away. I think that’s entirely possible,” Krikorian said.

Matt Towery, an Atlanta-based political consultant and former political adviser for Gingrich, thinks otherwise. He said he conducted an overnight poll after the debate that showed Gingrich’s poll numbers continuing to rise. Gingrich’s position is nuanced and qualified enough to fit in the conservative worldview, Towery said, and he just needs to explain it better.

“Do I think this is a bump in the road for Newt? The answer is yes,” Towery said. “Do I think it’s detrimental to his campaign? The answer is no.”