President Donald Trump's threat to send U.S. troops to hunt Mexico's "bad hombres" evokes the memory of a failed military operation a century ago, when General John "Black Jack" Pershing crossed the border at the head of a military unit in search of revolutionary leader Pancho Villa.
News of Trump's unusual comment came to light a few days ago, forcing both countries to scramble to contain the scandal.
Trump suggested the military solution in a call late last month to Mexican President Enrique Peña Nieto, according to several media that published a transcript of the exchange.
Trump apparently asserted that U.S. troops would arrest "bad hombres," using the phrase he made notorious during the election campaign to describe Mexican drug traffickers and undocumented immigrants he considers criminals.
In Mexico, any reference to a violation of sovereignty ignites nationalist sentiment, especially if the alleged threats come from the United States. This is the country that annexed much of Mexico's territory - including California, Arizona and Nevada - after the War of Mexico (1846-48).
Decades before that annexation, the United States hunted for Pancho Villa. The operation may be known north of the border as the "Mexican Expedition" but historians told Univision News it was more like a full-blown invasion.
It began on March 16, 1916 and lasted almost 11 months, during which time the United States and Mexico moved to the brink of war.
At the time, Pancho Villa controlled much of northeastern Mexico and had allied himself with Emiliano Zapata to overthrow de facto president Venustiano Carranza. U.S. President Woodrow Wilson regarded Carranza as Mexico's legitimate head of state and hoped that by supporting him, he could end the instability that had prevailed in the neighboring country since the beginning of the revolutionary period in 1910.
The border was a porous region and Pancho Villa's rebels made continuous incursions into the United States, where they received support from Americans sympathetic to their cause. On March 9, 1916, Pancho Villa's forces penetrated three miles into the United States and attacked Columbus, a town of 300 people in New Mexico, killing 16 Americans.
For Wilson that attack was the last straw, says historian Linda Hall, co-author with Don Coerver of Revolution on the Border. The president was worried he would be seen as weak, given his refusal to intervene in Europe during World War I.
But he knew that if he ordered an invasion to restore order, he risked triggering a war between the two countries.
Wilson gave in to those who demanded armed action and with the permission of Carranza sent General John "Black Jack" Pershing to the front with about 5,000 soldiers and an order to capture Pancho Villa. In that unit was George Patton, the heroic general of World War II, who had his baptism of fire in Mexico.
As the U.S. president feared, the operation severely worsened relations with Mexico. Although Wilson had obtained Carranza's permission, Pershing's men penetrated further into Mexican territory than had been agreed. Mexicans feared the real purpose of the operation was a new annexation of territory.
In photos: The last invasion of Mexico by the United States. 100 years before Trump.
On the brink of war
Pershing's forces met strong opposition, not only from the rebels of Pancho Villa, but also from those loyal to the Carranza government. The crisis reached its worst moment on June 21 with the Battle of Carrizal in Chihuahua, which claimed the lives of 14 U.S. soldiers and 27 Mexican soldiers.
With the countries on the brink of war, both governments sought a peaceful resolution in negotiations in New London, Connecticut, on September 6. In a settlement finally agreed on Christmas Eve, Pershing's troops could stay in Mexico as long as was needed. That raised much suspicion in Mexico about the possibility of an indefinite U.S. presence in the territory.
By then, the American public was already more concerned about the Great War in Europe, which the U.S. would enter in April 1917. On January 27, Pershing received withdrawal orders, which were completed on February 5, 1917.
The U.S. would still make a couple of minor incursions in later years, according to historian Hall, but an invasion of the caliber of the expedition would never occur again. Some 3,600 men crossed into Mexico through El Paso, Texas, on the night of June 15, 1919, to repel Pancho Villa's forces who had invaded Juarez, across the border, and were firing into U.S. territory.
The operation lasted only one day. When Villa's forces withdrew from Juarez, the U.S. military returned to El Paso.
Two months later, a group of U.S. soldiers moved against the Mexican bandit Luis Rentería, who had kidnapped two injured pilots at the border. The raid ended August 23, after five days and amid protests by the Mexican government over the invasion of its territory.
The "Mexican Expedition" and subsequent incursions were followed by a period of good relations between both countries. The symbol of this was the visit of the new Mexican president, Álvaro Obregón, to Texas.
Governor William Hobby said: "I want Mexico and the United States to be colleagues," and gave a nod to a successful comic strip of the moment: “In fact, I want them to be Mutt and Jeff from the Western Hemisphere."
The last time U.S. threats were heard again was 1938, when Mexican President Lázaro Cárdenas nationalized the oil industry. But U.S. President Franklin Roosevelt resisted the pressure of corporations and public opinion and opted for a diplomatic solution.
This was partly because he had to keep his southern neighbor as an ally at a time when the world was preparing for another great war.
Although Mexican suspicion of the United States persists, in the last three decades the two countries have grown closer and, until Trump’s rise to power, Mexican attitudes toward its northern neighbor had improved greatly. In recent years, U.S. soldiers and intelligence agents have worked hand-in-hand with Mexicans in the fight against drug-trafficking, albeit covertly and on a small scale.
The "Mexican Expedition" is an episode eclipsed in the collective Mexican memory by the U.S.-Mexico War of the 1840s, according to Alejandro Quintana, a history professor at St. Johns University. "In the end, the Americans were made to look ridiculous by General Pershing's operation. Pancho Villa fought them and they left empty-handed – a point of pride for Villa for many years."
Quintana finds it difficult to imagine U.S. troops in Mexico again, even with the consent of the neighboring country. Any incursion "would be a scandal, an aggression which would cause all of Latin America to rise up."
"What Trump is doing is anachronistic. He sees Mexico as a competitor and not a partner,” he said. “For a long time, from independence to the 1930s, the U.S. treated Mexico with arrogance, not as an equal."