As Trump announced he would raise tariffs on Mexican goods, the president of Mexico published an open letter to Trump.

In his letter, López Obrador asserts that tariffs aren't the way to solve the migration issue. (Photo: Pedro Pardo/AFP/Getty Images)

On Friday—the same day that President Donald Trump announced plans to impose new tariffs on Mexican goods to try to strong-arm the Mexican government to "halt the illegal flow of migrants" to the United States—Mexico's president published an open letter to Trump.

"Remember that I do not lack bravery, that I am not a coward nor timid, but rather I act on my principles," writes President Andrés Manuel López Obrador, known in his country as AMLO.

This is not the first time López Obrador has addressed Trump directly. In addition to the open letter he sent Trump when he first took office, AMLO published an entire book called Oye, Trump—"listen up, Trump"—in 2017. The book collects portions of López Obrador's speeches in which he spoke about the U.S. president, including one in which López Obrador declares that Trump and his advisers "speak of Mexicans the way Hitler spoke of the Jews" just before the Holocaust.

Compared to Oye, Trump, López Obrador's letter on Friday remained congenial but firm. Here are some key takeaways.

Asserting the Human Rights of Migrants

Contrary to Trump's rhetoric, under López Obrador, the Mexican government has continued a massive crackdown on immigration from Central America through the country. But López Obrador has shown a public willingness to frame the problem more as a refugee issue than an illegal immigration crisis.

"Human beings do not abandon their homes because they want to, but rather by necessity," AMLO writes. He also maintains that his government has complied with its responsibility to prevent migrants' passage through Mexico, but only to the degree that such methods are "possible without violating human rights."

Lessons From the Decrease in Mexican Migrants to the U.S.

In the last decade, the number of Mexicans migrating to the U.S. has plummeted. As the Mexican economy improved and the U.S. experienced a recession in the late 2000s, Mexican border crossings dropped by over a million per year, to just a few hundred thousand today.

AMLO points to this trend to propose a solution to the migration crisis. "Soon, Mexicans will not face the necessity of coming to the United States, and migration will be optional, not forced," he writes. He says that the diminishing number of Mexican migrants comes from Mexico's efforts to combat corruption and poverty and to improve the social sphere.

As Mexican migration has fallen, rates of Central American migration have risen rapidly. To solve the problem, AMLO proposes multi-national cooperation efforts to develop and aid Central American countries.

'Social Problems Can't Be Resolved With Tariffs or Coercive Methods'

Halfway through his letter, López Obrador addresses Trump directly and asserts that tariffs aren't the way to solve the migration issue. He decries efforts to keep migrants in a "ghetto," and to turn away people fleeing persecution. "The Statue of Liberty is not just an empty symbol," López Obrador writes.

'America First Is a Fallacy'

In his letter, López Obrador shows an appreciation of U.S. history: He mentions the cooperation between Benito Juárez (Mexico's first indigenous president) and Abraham Lincoln, and he heaps praise on Franklin Delano Roosevelt, calling him "a titan of liberty."

But the Mexican president goes on to assert that Trump's "American First" policy is misguided. "With all due respect, although you have the right to express it, 'America First' is a fallacy because until the end of time, beyond national borders, justice and universal fraternity will prevail," he writes.