WASHINGTON – The glow may be dimming on the halo conservatives positioned over the head of Sen. Marco Rubio as he pushes ahead with immigration-reform legislation that has been almost universally panned by the right wing of the Republican Party.

Once considered the frontrunner for the 2016 GOP nomination, the Florida lawmaker has run into a buzzsaw wielded by the Tea Party and others who condemn anyone for straying from what they consider conservative orthodoxy. Many now view Sen. Ted Cruz (R-Texas), the son of Cuban immigrants who was charged with introducing the Republican nominee Mitt Romney at the Tampa convention, as better presidential timbre than Rubio.

Rubio has staged a full-court press over the past month, appearing on various right-wing radio talk shows and Fox News to explain his position and firm up his conservative bona fides. His Senate staff has issued numerous statements countering what they consider erroneous or unfair comments about Rubio and the legislation.

The effort hasn’t been totally successful. National Review, the magazine launched by the late William F. Buckley that sparked the conservative movement, offers an unflattering look at Rubio in its May 20 edition. The cover photo shows him positioned between Sens. Chuck Schumer (D-N.Y.) and John McCain (R-Ariz.), two allies on the immigration endeavor, with the headline “Rubio’s Folly” prominently featured.

On Thursday about two dozen protesters gathered outside the site of the Lincoln Day Dinner, a fundraiser Rubio was attending in St. Lucie County, to voice opposition to his involvement in the immigration legislation.

“He was the Tea Party darling. Until he went to D.C. and played us,” Christine Timmon, a Tea Party supporter, told WPTV-TV in West Palm Beach, Fla.

The Tea Party Patriots, a major conservative movement group, took aim at Rubio by staging what was termed a “D.C. intervention,” consisting of disgruntled representatives from the organization protesting at his Florida offices.

In a release the group characterized Rubio as “the star spokesman for a secretive, small group working on a bill that purports to address illegal immigration and the entire US immigration system as a whole.”

“Not only might the legislation be bad policy, it has already gone outside of the normal process,” the group said.

Rubio responded to the group by saying, “Immigration reform is a difficult issue. It represents the kind of broken government that Tea Party members across our country were fed up with in 2010, and an issue that inspired me to run in order to change the way Washington works.”

Daniel Horowitz wrote on Red State that Rubio’s position is counter to what he said during his successful election campaign in 2010.

“Look, there’s nothing new about politicians ‘evolving’ shortly after being elected to Congress, but how could someone evolve so profoundly in such short order?” Horowitz asked.

Speaking to loyal Republicans in Pasco County, Fla., on Wednesday, Rubio acknowledged “there will be no parade for me on this issue” but indicated he remains unwilling to abandon the fight.

“I ran because I wanted to fix things that I thought were hurting America — that’s what I tried to do on this issue,” he said. “To people who don’t like that solution, all I ask is, ‘What’s yours?’”

Rubio is part of what has been dubbed the Gang of Eight, a bipartisan group working to overhaul the nation’s immigration laws. The legislation, issued on April 16, permits undocumented immigrants who entered the U.S. before Dec. 31, 2011, and remained exclusively in country thereafter to apply for what is being called provisional legal status. That would allow them to remain and work in the U.S. although they would have to wait more than 10 years to attain full citizenship.

About 11 million undocumented immigrants live in the U.S.

The measure also spends billions of dollars strengthening border security, concentrating on what are considered high-traffic zones. But conservatives opposed to the bill, which is slated for initial consideration before the Senate Judiciary Committee on May 7, consider it an amnesty that violates conservative principles.

Rubio has expressed some qualms about the legislation, particularly the sections dealing with border security that he would like to see strengthened. Regardless, speaking to radio host Mike Gallagher on Tuesday, he acknowledged the Senate bill wouldn’t make it through the House in its current form, a factor that doesn’t faze him.

“The bill that’s in place right now probably can’t pass the House,” Rubio said. “It will have to be adjusted, because people are very suspicious about the willingness of the government to enforce the laws now.”

Despite the apparent political stumble, Rubio has a leg, albeit short leg, up on the rest of the 2016 GOP field, according to a recent poll. A Fairleigh Dickinson University poll released April 30 showed him attracting 18 percent of the Republican primary vote with New Jersey Gov. Chris Christie, who also has attracted conservative thunder for praising President Obama’s reaction to Hurricane Sandy, coming in second with 16 percent. Former Florida Gov. Jeb Bush was third with 14 percent.

And while many conservatives have assumed a jaundiced view of Rubio, talk radio seemingly remains firmly in his corner despite claims by pollster Frank Luntz that several powerful hosts are “destroying” him. The big three – Rush Limbaugh, Sean Hannity, and Mark Levin – continue to heap praise on Rubio throughout the debate while simultaneously raging against the immigration bill he’s championing.

Hannity, who follows only Limbaugh among talk show hosts, remains particularly effusive, telling Rubio during a May 1 appearance on his program, “I have faith in you. I think if you were in control…I’d trust you!”

“I’ve gotten to know you and your family and I hear your conservative message and I think you have all the right intentions,” Hannity said.

Limbaugh acknowledged that Rubio is “a little naïve on the immigration stuff” but characterized him as “a good person” on his April 30 show.

“The reason I say he’s a force, there’s no question this guy is one of the few real conservatives in elected office today, folks,” Limbaugh said. “There’s no question about that.”