Editor's note: Ruben Navarrette Jr. is a nationally syndicated columnist, an NPR commentator and a regular contributor to CNN.com

Phoenix, Arizona (CNN) -- By spending a few days here in America's fifth-largest city -- which also happens to be at the heart of the nation's immigration debate -- I had the chance to see this volatile issue from many different vantage points.

But as far I know, I didn't see any terror babies.

Regular viewers of CNN's "Anderson Cooper 360" will recognize that term as referring to children born on U.S. soil to illegal immigrants. The children are automatically granted U.S. citizenship under the 14th Amendment and then are smuggled back to their home countries to be raised as pint-sized, America-hating terrorists. Then decades later, when the children have grown into adults, they could easily -- because of their U.S. citizenship -- re-enter the United States to attack it from within.

So terror babies are sort of like a sleeper cell, one that has to be put down for a nap every few hours or it gets fussy.

Is this a scary scenario? You bet. Is it anything close to reality? It doesn't look like it. In fact, what's really scary are opportunistic lawmakers out there who will sink to new depths to scare the Dickens out of people in order to drum up support for the radical idea of changing the 14th Amendment or scrapping it altogether.

That's what this story is really about. It's an elaborate pitch to that constituency who believes that illegal immigrants are unfairly taking advantage of a constitutional provision that makes anyone born on U.S. soil an American citizen.

The two Texas Republicans who are actively spinning this yarn -- State Representative Debbie Riddle and U.S. Congressman Louie Gohmert -- both appeared on Cooper's show this week, and neither could provide any evidence of the existence of these mythical terror babies. In fact, in the face of questioning by Cooper, both got extremely defensive. You might say these GOP fear mongers were acting in a way that could be accurately described as infantile.

Riddle and Gohmert claimed they got the information from conversations with "former FBI officials." So Cooper interviewed CNN contributor Tom Fuentes, who served as the FBI's assistant director in the office of international operations from 2004 to 2008.

"The FBI has 75 offices overseas, including offices in Jordan, Turkey, Israel, Saudi Arabia, Yemen, Pakistan," Fuentes said. "There was never a credible report -- or any report, for that matter -- coming across through all the various mechanisms of communication to indicate that there was such a plan for these terror babies to be born."

The FBI has also done everything it can to knock down the story as simply not credible.

Of course, this tall tale isn't credible; it's probably nothing more than a figment of politicians' imaginations. But it is valuable since it helps illustrate a disturbing phenomenon here in Arizona, where supporters of the state's new immigration law seem to feel as if they have to justify the measure not only by scaring people, but also by doing extreme makeovers. They take things that are familiar and try to make them sinister.

Those aren't U.S. citizen babies, they say; they're future terrorists. Those aren't run-of-the-mill illegal immigrants who come to Arizona to work and feed their families; they're drug mules for the Mexican cartels, says Arizona Gov. Jan Brewer. And those aren't coyotes, immigrant smugglers bringing people in the United States as they have for generations; they're drug cartels, which -- according to Brewer -- now control all the immigrant smuggling operations into the United States.

The Border Patrol was just as quick to knockdown those stories as untrue as the FBI was in refuting the story about terror babies using the 14th Amendment to do us harm.

I was glad to see that. There is already enough dishonesty in the immigration debate; we certainly don't need any more coming from the state of Arizona. Yet, there is a steady trickle of deceptions and half-truths.

The three big fibs -- repeated by top Republican officials -- are that the federal government isn't doing its job to protect the borders, that the law is an attempt to crack down on drug cartels, and that race isn't part of the discussion. None of that is true. So why repeat it?

Those who believe in the state's immigration law and consider it a good idea to empower local police and sheriff's deputies to enforce federal immigration law should stand by the legislation as it is written. They shouldn't have to try to create an alternate reality to win over more supporters.

A prominent Mexican-American attorney, who has long been a visible and vocal member of Phoenix's Latino community, warned me against trying to make sense of the opposition.

For instance, I asked him, how could people continue to argue that the Obama administration isn't doing enough to secure the border when all the evidence suggests otherwise?

"You'll never be able to convince people of that," he said. "Because their motivation is political. It's not based in reality."

I'm afraid that's not good enough. If the supporters of SB1070 really believe in the merits of their cause, they should be able to win the argument on the natural, without relying on hocus-pocus or scare tactics or radical makeovers. And if they can't do that, if they have to portray babies as terrorists and immigrants as drug mules in order to win support for their side, then this should tell them loud and clear that they're on the wrong side of this issue -- not to mention, on the wrong side of history.

No amount of spin can change that.

The opinions expressed in this commentary are solely those of Ruben Navarrette Jr.