John Diaz: Trump’s drumbeat against illegal immigration pervaded the GOP convention.

Claudia Ruiz Massieu, Mexico’s foreign minister, was extolling the gathering at San Francisco Art Institute with numbers and anecdotes about U.S.-Mexico trade. She noted that 6 million jobs nationwide — 700,000 in California — result from that relationship. She spoke in warm terms about the cultural ties between the two countries. Her visit to the city coincided with Monday’s opening gala of the third annual Mex-I-Am celebration, followed by a Tuesday dedication to the Mexican Museum.

Two thousand miles away, a much darker, and less factually grounded, portrayal of immigration’s impact on the United States was off and running at the Republican National Convention in Cleveland.

The Republicans’ opening night featured three speakers who lost a loved one through the fault of an immigrant who was in the U.S. illegally.

“My son’s life was stolen at the hands of an illegal alien,” Mary Ann Mendoza said. Her son, Brandon, was a Mesa, Ariz., police officer killed in a 2014 head-on crash with an intoxicated wrong-way driver.

Each case was beyond heartbreaking. Yet these three deaths, outrageous as each was, do not validate the Trump campaign’s premise that the border is out of control and that masses of criminal immigrants are “roaming free to threaten peaceful citizens,” as the candidate warned in his acceptance speech.

In fact, U.S.-Mexico immigration has stabilized in recent years, with as many Mexicans leaving as entering this nation. The notion that President Obama has somehow been passive on the issue is contradicted by the fact that his administration has deported more people (more than 2.5 million) than any in history.

As for the fear factor that was fanned so rabidly all week in Cleveland: Various state and federal studies have found no basis to conclude that immigrants, legal or otherwise, are more prone to violent crime.

And still the drumbeat against illegal immigration pervaded all week in the convention that nominated the billionaire real estate mogul who began his campaign by accusing Mexico of sending rapists and drug dealers northward.

Perhaps the ultimate slap at Latinos came when Sheriff Joe Arpaio was given a prime speaking slot. Arpaio is the sheriff from Maricopa County, Ariz., whose overzealous immigration raids have drawn national attention. A federal judge found the self-proclaimed “America’s toughest sheriff ” in contempt of court earlier this year for defying an order to stop racial profiling of Latinos.

This GOP immigrant bashing can carry a heavy price. In reality, a significant portion of legal immigrants object to illegal immigration. But when a politician or party rails against an immigrant group with a broad brush, it gets personal.

It certainly did in California, where Gov. Pete Wilson’s shrill advocacy of a 1994 initiative to deny public benefits to immigrants in the U.S. illegally has had lasting effect on voting patterns of the state’s fastest-growing demographic group. Republicans registration in the state has fallen to 27 percent.

House GOP Leader Kevin McCarthy said he told Trump he would need to get at least 40 percent of the Latino vote in California to win the state’s 55 electoral votes. The Republican National Committee’s own internal autopsy of Mitt Romney’s 2012 defeat concluded that reversing its dismal standing with Hispanics and other minority groups was essential to the party’s long-term prospects.

A Wall Street Journal/NBC News poll last week had Trump at 14 percent among Hispanic voters nationally.

Garry South, a prominent Democratic consultant from Los Angeles, said the posturing could have extended damage to Republicans. South noted that Asian Americans are increasingly voting for Democrats. In 2012, nearly 3 in 4 voted to re-elect President Obama.

“These (Republicans) are thinking about brown faces coming across the Rio Grande ... but guess who else is listening?” said South. “Asians are the besteducated minority group, they’re the highest-income minority group, and they’re not stupid. So when they hear all this anti-immigrant rhetoric — even though it’s intended to be aimed at Mexicans and Guatemalans and all that — they hear it, they internalize it, and they’re offended by it.”