There is only one power that Mr. López Obrador, popularly known as AMLO, recognizes and fears, and that is the only power greater than himself — the United States. A saying that he is fond of alludes to the futility of trying to take down Samson in a fistfight. Having cut his teeth in Mexico, where presidents used to reign as emperors, Mr. López Obrador equates Samson and the United States with Donald Trump.

That’s why when Mr. Trump threatened to abandon the North American Free Trade Agreement or to impose tariffs on Mexican products, he agreed to turn Mexico into Mr. Trump’s wall. The new National Guard, which was supposed to prevent and combat this country’s unspeakable drug violence, has instead been deployed on our southern border turn away Central American migrants and, on the northern border, to keep them penned up in subhuman conditions.

Until Trump, servility was never the hallmark of Mexican diplomacy vis-à-vis the United States. In the nearly two centuries of relations between our countries, full of diplomatic and military conflicts, there have been only a handful of episodes in which Mexican leaders, driven by fear and necessity, prostrated themselves before “the giant of the north” — most famously the Mexican-American War, which ended in 1848 with Mexico ceding more than half of its territory to the United States. And in 1859 Benito Juárez and James Buchanan signed a treaty that, had it not been for the outbreak of the American Civil War, would have resulted in the additional loss of sovereignty.