Editor's note: Ruben Navarrette Jr. is a CNN.com contributor and a nationally syndicated columnist.
San Diego (CNN) -- In a popular fable, a scorpion asks a frog to carry him across a river. The frog resists at first, afraid that the scorpion will sting him. The scorpion points out that -- as a practical matter -- if he stings the frog, they both die. The frog gives in. Halfway across, the scorpion does in fact sting the frog and they both drown. Why would the scorpion do that, the frog asks. The scorpion responds that he can't help it, that this is his nature.
The moral: Some creatures can't control their natural impulses, even if it would lead to their own demise.
It's the same way with Republicans when they discuss immigration, as the four remaining GOP presidential hopefuls did Wednesday night during the CNN debate in Mesa, Arizona.
Yes, that Arizona. This is, after all, the state where lawmakers, in 2010, started a poisonous national trend by approving what was up to that point the toughest immigration law in the country, not to mention one of the most constitutionally flimsy, judging by the fact that a federal court a few months later struck down most of the measure, saying that the state had overstepped its authority in trying to regulate federal immigration policy.
Arizona's stringent immigration law, known as SB 1070, essentially sanctions ethnic profiling by forcing local and state law enforcement officers to determine the citizenship of anyone they suspect is in the country illegally. In Arizona, that kind of language targets Latinos -- plain and simple. This isn't just offensive, but also ironic given that there have been Latinos in the state since before the U.S. acquired it during the U.S.-Mexican War of 1847.
So, it was expected that the Republican candidates would be asked about immigration during the debate. But did they have to do such a poor job of responding? Couldn't they have, for just one night, ditched the sound bites, put on ice the pandering to nativists and restrictionists in the GOP base, and been more thoughtful and candid about how we got here and what we should do now?
The stakes are high. If the GOP doesn't get immigration right, it will be DOA. Republicans won't be winning many presidential elections for the rest of this century if they continue to alienate Latino voters because of the cruel, arrogant, simplistic and dishonest way in which many of them approach this vexing issue.
Demographics are not on their side; U.S Census officials estimate that Latinos could account for as much as 30% of the population by 2050. As many as 10 million Latinos are expected to cast ballots in the 2012 election. And every year, another 500,000 U.S.-born Latinos reach voting age.
Yet it is in the Republicans' nature to talk about immigration in ways that downplay the responsibility of U.S. employers that hire illegal immigrants; portray illegal immigrants as takers and freeloaders who sponge off hard-working Americans; deny that -- as Florida Sen. Marco Rubio said recently -- some of the rhetoric coming from their base is "harsh, intolerable and inexcusable"; and reinforce the narrative that states like Arizona were flooded by illegal immigrants through no fault of their own and now have to do everything they can to secure the U.S.-Mexico border and run off intruders.
Meanwhile, out of Wonderland and back in reality, we know that we wouldn't have illegal immigrants if we didn't have people hiring them for their strong work ethic and willingness to work cheaply. And we know that those illegal immigrants contribute to the economy by doing jobs that Americans won't do. Rubio is right that Republicans go over the line with their rhetoric, which often starts out as anti-illegal immigrant but winds up sounding anti-Latino. States like Arizona -- in fueling its own growth and development during the 1990s -- all but recruited the same illegal immigrant population they now complain about, and the Obama administration has gone overboard in enforcing immigration law by deporting more illegal immigrants than any administration in half a century -- 1.2 million and counting.
No Republican presidential hopeful had the guts to say any of that Wednesday night. There were no heroes on that stage, no profiles in courage, no one willing to tell the crowd gathered in Arizona not what they wanted to hear, but what they needed to hear.
When someone from the audience -- who identified himself as Jerry Lott from Key Man, Arizona -- got the discussion going by suggesting that the state was "under federal attack just for wanting to secure the border," no one corrected him. Not one of the Republican candidates for president pointed out that the federal government was suing Arizona not for trying to keep out additional illegal immigrants along the border, but for mistreating people who are already here, including many U.S. citizens who deserve better.
Remember, these are the same Republicans who -- in the foreign policy space -- are trying to convince voters that they'll stand up to thugs, tyrants and madmen in an unfriendly world.
Sure. These cowards don't even have the courage to go before a friendly audience and stand up for the truth.
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The opinions expressed in this commentary are solely those of Ruben Navarrette Jr.