Who you gonna call when your first phoner to Mexico’s president goes south, your Secretary of State’s first visit there is not exactly a fiesta — and suddenly it’s not just jobs but U.S. tech innovation finding sanctuary in Mexico’s version of Silicon Valley?

Easy. Find a guy who’s very simpatico, who is más macho than you. President Trump, say hello to Harry S. Truman.

In 1947 President Truman visited Mexico City. No American president had visited the capital and thousands jammed the streets. One woman shouted, “Viva Missouri!” while the president passed and shook hands with the crowd.

Truman later told Mexico’s legislature he had never experienced such a welcome. In turn, he re-affirmed Roosevelt’s Good Neighbor Policy, making an unscheduled stop at Chapultepec Castle, Mexico’s historic military academy and royal palace.

Chapultepec is sacred ground in Mexico. Here, six military cadets died defending the castle in 1847 during the Mexican-American war. One of them according to legend, leaped to his death wrapped in the Mexican flag rather than surrender.

Here, Truman placed a wreath and bowed his head. With this one show of respect, the man from Independence did more to improve Mexican-American relations than any U.S. president in a century.

“Brave men don’t belong to any one country,” he said. I respect bravery wherever I see it.”

Truman learned a lesson that has escaped Trump. In Mexico, the art of the deal is understanding the nature of culture on both sides of the border.

Let’s start with some history. For example, there was repatriation in the 1930s of about a million people from the United States back to Mexico. The goal was to reduce the number of families and individuals on government relief. It’s estimated 60 percent of the people caught up in the Mexican repatriation drive were actually U.S. citizens of Mexican descent.

In the 1940s, America suddenly needed those Americans back as cheap farm labor, and the Bracero Program was created. It offered employment contracts to 5 million braceros in 24 U.S. states, becoming the largest foreign worker program in U.S. history.

And let’s not forget the U.S. invasion of Mexico. Both Abraham Lincoln and U.S. Grant opposed that war, understanding its “manefest destiny” was actually a plan to acquire slave state territory for the Union.

President Truman realized that, in Mexico, the art of the deal is about taking time to get to know your counterpart. You have dinner. You have a drink. Or two. Then, in a gesture that turned out to be worth 1000 dinners, Truman visited Chapultepec.

Which brings us back to that call between Trump and Enrique Peña Nieto. Since then, a threat to invade Mexico was excused as light banter and immigration round-ups ramped up.  Mexico’s response: cancellation of sugar export permits to the U.S. and sanctuary to highly skilled tech workers who find themselves no longer welcome in the U.S.

Mexican Foreign Minister Luis Videgaray says reconciliation must be based on facts. Let’s look at the facts:

U.S. farmers need Mexico’s farm imports — more than $17 billion, according to U.S. government data. Those imports support American jobs. Now, Mexico is offering jobs, federal and state subsidies, education grants and favorable migration policies to skilled U.S. workers.

But facts need context to be understood. And context lives in history and heritage. In Mexico a special place, full of grace, provides both: the Basilica of Our Lady of Guadalupe, where solace and protection are not bartered.

Here is where President Trump should go and contemplate history. This simple act of contrition would be worth more than 1000 presidential dinners. It would show respect and humility – just the sort of grace you’d expect from a good neighbor.

Marcela Davison Aviles is managing director and executive producer of Camino Arts and consulting Director of Humanities Programs for the FDR Foundation. She wrote this for The Mercury News.