Happy St. Patrick's (Battalion) Day!

During the buildup to the Mexican-American War (1846-1848), scores of immigrant Irishmen joined the army for the monthly payment of $7. 

"The U.S. anti-immigrant press of the time caricatured the Irish with simian features, portraying them as unintelligent and drunk and charging that they were seditiously loyal to the pope," Anne-Marie O'Connor wrote in the Los Angeles Times. "But cheap Irish labor was welcome.”

After President James K. Polk incited hostilities by sending U.S. troops into disputed territory, many of those Irish soldiers (who found themselves heading west to fight a war of conquest) were Catholic.

"This is a story about assimilation," historian Peter F. Stevens adds. "A lot of these guys deserted because of the anti-Catholic, anti-foreigner movement.”

One such deserter was John Riley, an Irishman from Galway who swam across the Rio Grande after asking permission to go to Mass.

"As the U.S. Army marched through Mexico's northern deserts, others followed, and Riley became captain of a 200-member rogue column in the Mexican army," explained O'Connor. "At San Luis Potosi, convent nuns presented them the hand-stitched banner that foreshadowed their eventual romanticization.”

A wartime newspaper correspondent from New Orleans described the banner as made of "green silk, and on one side is a harp, surmounted by the Mexican coat of arms, with a scroll on which is painted, 'Libertad para la República Mexicana.' Underneath the harp is the motto 'Erin go Bragh' (Ireland for Ever). On the other side is a painting ... made to represent St. Patrick, in his left hand a key and in his right a crook or staff resting upon a serpent.”

The group was unofficially known as the "Irish Volunteers," but Mexicans often referred to the redheaded and ruddy-complexioned men as the "Red Guards." Formally, the unit was called the "San Patricio Company," a title that evolved into the more familiar "St. Patrick's Battalion."

Please allow me to offer a little context as to how this war came to be. It should sound mighty familiar to anyone who's been paying attention.

When James K. Polk was elected U.S. president in 1844, he had every intention of creating a pretext to stir Americans into action against Mexico. One of the issues of the 1844 election was the annexation of Texas-or “reannexation,” as Polk called it. Apparently, no one bothered to remind him that Texas was not part of the original Louisiana Purchase.

When Mexico gained independence from Spain in 1821, the territory of Texas (along with what are now New Mexico, Arizona, Nevada, Utah, California, and part of Colorado) was Mexican territory. Fifteen years later, Texas claimed its independence as the Lone Star Republic. In Washington, it was viewed as U.S. property.

“Even before Polk’s inauguration, Congress adopted a joint resolution on his proposal to annex Texas,” explains historian Kenneth C. Davis. “When Mexico heard of this action in March 1845, it severed diplomatic relations with the United States.”

Undeterred, Polk sent an ambassador, James Slidell, to negotiate a purchase of Texas and California. Slidell was rebuffed. Polk took a new tack and ordered General Zachary Taylor to lead his troops all the way to the Rio Grande, thus testing the defined borders.

“Mexico claimed that the boundary was the Nueces River, northeast of the Rio Grande, and considered the advance of Taylor’s troops an act of aggression,” says Davis. Colonel Ethan Allen Hitchcock, commander of the 3rd Infantry Regiment, said of this move, “It looks as if the government sent a small force on purpose to bring on a war, so as to have a pretext for taking California and as much of this country as it chooses.”

The pretext arrived on cue when Polk ordered Taylor and his 3,500-member “Army of observation” to cross the Rio Grande. Taylor’s quartermaster, Colonel Cross went missing, his body was found 11 days later with his skull crushed. The day after Cross’ high-profile public funeral, a patrol of Taylor’s soldiers was attacked by Mexicans. Sixteen were killed.

Taylor sent a dispatch to Polk: “Hostilities may now be considered as commenced.” Declaring “the cup of forbearance” to have been exhausted, Polk announced to Congress, “War exists.”

In five major battles, the San Patricios earned a reputation for bravery that peaked Aug. 20, 1847, at Churubusco where, over the course of three hours, 60 percent of the San Patricios were killed or captured by a numerically superior American army. One of the prisoners was Brevet Major John Riley.

"At their court-martial," O'Connor stated, "most San Patricios said they had been forced to desert by the Mexicans or had too much to drink.”

"They needed an excuse. They couldn't say "I hated the United States," so they said they weren't responsible," said Miller. In some cases — including Riley — this defense was effective. While 50 San Patricios were sentenced to death, five others were pardoned and 15 others received a reduced sentence.

Riley himself was given 50 lashes and was hot-iron branded with a two-inch letter "D" for Deserter. The San Patricios who faced the gallows were hanged in their Mexican uniforms and buried in graves dug by Riley and the other branded prisoners. 

The war was over and in the name of historical cleansing, the legend of St. Patrick's Battalion was essentially banished north of the border.

Coda: Ulysses S. Grant later called the Mexican-American War “one of the most unjust ever waged by a stronger against a weaker nation.” In retrospect, it can be more accurately described as merely a preface in the U.S. military intervention playbook.