SAN DIEGO, California (CNN) -- If Hillary Clinton loses the Democratic nomination for president, she might be able to trace her troubles back to when she lost her grip on the Latino vote.

Ruben Navarrette Jr.: Sen. Barack Obama belatedly but quickly found the importance of courting Latinos.

Bill Clinton called it. The ex-president may have doomed his wife's candidacy with his meddling but he was right about one thing: Several weeks ago, he told Spanish-language radio host Eddie "El Piolin" Sotelo that Latinos would "determine the nominee of the Democratic Party and the next president of the United States."

So they might. Just not in the way that the former president imagined.

When he made his prediction, Hillary Clinton was leading Barack Obama among Latinos by a 2-1 margin. No mas.

A recent Gallup survey found Obama in a slight, but not statistically significant, lead over Clinton among Latinos. Obama-mania has gone multicultural. And it's about time.

The Illinois senator spent so much of the early part of the campaign proving he could appeal to both blacks and whites that he never stopped to ask: "What can brown do for me?" As a result, Obama fumbled in the Nevada caucus.

But he recovered in time to fare better than expected on Super Tuesday.

He won the Latino vote in Illinois and Colorado and stayed competitive in New Mexico and Arizona, even while getting wiped out in California, New York, and New Jersey.

Then he won the Latino vote in Virginia. Now, with the all-important Texas primary approaching on March 4th, Obama is trailing Clinton with Latinos in the Lone Star state but he's making inroads there.

There is even a "Viva Obama" video featuring a group of mariachis singing the candidate's praises. Obama's recent success with Latinos is evidence that Hillary's support in that community is a mile wide and an inch thick.

That's understandable. Neither Bill nor Hillary Clinton has done much for Latinos in their public careers, and most of the support they enjoy from that community comes from brand loyalty -- the same thing that keeps Latinos coming back to one kind of laundry detergent keeps them coming back to the Clinton name.

In this election, Hillary has tarnished the brand with mistakes. During a debate in Los Angeles, she answered a question by pitting undocumented Latino immigrants against African-Americans.

She blamed jobs losses on "employers who exploit undocumented workers and drive down wages." And she mentioned an African-American who told her that he used to have construction jobs but now "the only people who get them anymore are people who are here without documentation."

Faced with the same question, Obama pointed out that African-Americans had high unemployment rates long "before the latest round of immigrants showed up" and cautioned against using the immigration issue to divide Americans.

Obama also insisted -- to rousing applause -- that blaming immigrants for unemployment among blacks amounts to "scapegoating" and said he wouldn't tolerate it. Score one for Obama. You can almost hear the mariachis warming up.

The opinions expressed in this commentary are solely those of the writer. E-mail to a friend