Shamrock and Sword

1. The Saint Patrick's Battalion: A Unique Unit of U.S. Army Deserters

This outfit was unique in that it was composed primarily of deserters from the United States Army, virtually all of whom defected during the Mexican War.

A unique formation. The Saint Patrick's Battalion, or Batallón de San Patricio, was an extraordinary unit within the Mexican army during the U.S.-Mexican War (1846-1848). Unlike typical foreign legions, it was composed almost entirely of men who had deserted from the opposing United States Army. This made them a singular entity in military history, fighting against their former comrades under a distinctive emerald flag.

Diverse origins. While often romanticized as purely Irish Catholic, the battalion comprised men of a dozen nationalities, though Irish immigrants formed the largest contingent (about two-fifths). Other members included:

• Native-born Americans
• Germans
• Scots and English
• French, Italian, Polish, and Spanish-Floridian individuals
• Mexican citizens and foreign residents of Mexico

John Riley's leadership. The battalion's key figure and organizer was John Riley, an Irish immigrant who deserted from the U.S. Army in April 1846. He rose to the rank of major in the Mexican artillery, designed the unit's shamrock flag, and actively recruited over 150 men. His leadership provided cohesion for this diverse group, often emphasizing a superficial Irish-Catholic link that resonated more with Mexicans than with the varied San Patricios themselves.

2. Harsh U.S. Military Discipline Fueled Desertions

More persons have been shot or hung for various crimes by the American officers in Mexico during the past two years than would be capitally executed in the whole United States in the ordinary course of justice during ten years.

Brutal punishments. The U.S. Army of the era was characterized by severe and often unjust military discipline, which significantly contributed to widespread desertion. Soldiers faced barbarous punishments for even minor infractions, leading to deep resentment and a desire to escape the service. These included:

• Flogging (up to 50 lashes on the bare back)
• Branding with letters like "D" for deserter or "HD" for habitual drunkard
• The "buck and gag" (tied in a sitting position with a gag in the mouth)
• Being tied to a cannon or wagon wheel under the sun
• Imprisonment in small, inhumane cells

Officer tyranny. Many American soldiers complained bitterly about the brutality and tyrannical behavior of their officers. Instances of officers striking men with swords, verbally abusing them, and inflicting arbitrary punishments were common. This created a hostile environment where soldiers felt dehumanized and without recourse, further eroding morale and loyalty.

High desertion rates. The Mexican War saw the highest desertion rate of any American foreign war, exceeding 8% of the total force. This was double the rate of the Vietnam War. While some desertions were due to drunkenness or illness, the pervasive harsh discipline and perceived injustice were major underlying factors that pushed many men to abandon their posts, and in some cases, their country.

3. Mexican Propaganda and Promises Lured Foreign-Born Soldiers

The Mexican nation only look upon you as some deceived foreigners and hereby stretch out to you a friendly hand, offer you the felicity and fertility of their territory.

Appeals to faith. Mexican generals, particularly Santa Anna, actively sought to entice foreign-born, especially Catholic, soldiers to desert from the U.S. Army. They disseminated English-language handbills that played on religious sentiments, portraying the war as an "unjust, illegal and anti-Christian" aggression by a "heretic country" against a Catholic nation. These leaflets urged Irishmen to remember their shared faith and not fight against their "brethren."

Economic incentives. Beyond religious appeals, Mexico offered substantial material rewards to defectors. These promises were a powerful draw for poor, immigrant soldiers seeking a better life. Incentives included:

• Cash bonuses: $10 immediately, plus $5 for every comrade brought along.
• Land grants: A minimum of 200 acres for privates, increasing significantly with rank (e.g., 8,000 acres for a colonel), with additional acreage for each year of service.
• Military promotions: Deserters were often commissioned as officers, receiving significantly higher pay than their U.S. Army private salaries (e.g., Riley's pay jumped from $7/month as a U.S. private to $57/month as a Mexican lieutenant).

Sanctuary and respect. Mexican propaganda also promised defectors good treatment, hospitality, and a new home where they would be respected. This contrasted sharply with the nativist prejudice and discrimination many foreign-born soldiers experienced in the U.S. Army, where they were often taunted and passed over for promotion. The promise of a welcoming society, free from the "slavish hireling's life," resonated with those feeling alienated.

4. The San Patricios Fought Valiantly in Key Battles

Their deportment deserves the greatest eulogies, since all the time the attack lasted they sustained the fire with extraordinary courage.

Artillery prowess. The San Patricios, initially organized as an artillery company, demonstrated remarkable skill and bravery in several major engagements. Their expertise, often gained in the U.S. service, made them formidable opponents. They were particularly noted for their effective use of cannons, which often inflicted heavy casualties on American forces.

Key engagements: The battalion participated in crucial battles, leaving a significant mark on the war:

• Matamoros (May 1846): Assisted Mexican artillery in bombarding Fort Texas (later Fort Brown).
• Monterrey (September 1846): Employed in refurbishing, emplacing, and servicing cannons, contributing to the city's defense.
• Buena Vista (February 1847): Manned a battery of heavy guns, inflicting "gaping holes" in American ranks and capturing two U.S. cannons. Over a third of the company were killed or wounded, earning them "most consummate praise."
• Churubusco (August 1847): Their most famous stand, where they fought with "daring bravery" and "desperation to the last," tearing down white flags hoisted by other Mexican units.

Mexican recognition. Their valor earned them military decorations and high praise from Mexican commanders, including Santa Anna, who wished he had "a few hundred more men like them." This recognition underscored their commitment to their adopted cause, despite their origins as deserters.

5. Captured Deserters Faced Brutal U.S. Military Justice

The fourteen that were to be whipped and branded were tied up to the trees in front of the Catholic church on the plaza, their backs naked to the waistband of the pantaloons, and an experienced Mexican muleteer inflicted the fifty lashes with all the severity he could upon each culprit.

Swift courts-martial. Following the decisive battles of Contreras and Churubusco in August 1847, the U.S. Army captured 72 San Patricios. These men were swiftly brought before two general courts-martial, one in Tacubaya and one in San Angel, presided over by U.S. officers. The trials were expedited, with judges ordered to "sit without regard to hours."

Guilty verdicts and harsh sentences. Despite pleas of drunkenness, coercion, or being captured, 68 of the 70 San Patricios tried were found guilty of desertion and sentenced to death by hanging. General Scott, after reviewing the sentences, confirmed capital punishment for 50 men, while commuting the sentences of 15 others, including John Riley, due to their desertion occurring before the official declaration of war.

Public floggings and hangings. The punishments were carried out with public spectacle and extreme cruelty:

• Flogging and branding: 15 men, including John Riley, received 50 lashes on their bare backs and were branded with a two-inch "D" for deserter on their right cheek (Riley was branded twice due to an initial error).
• Mass hangings: 50 San Patricios were hanged in two separate events. 16 were hanged in San Angel on September 10, and 30 more were executed in Mixcoac on September 13, timed to coincide with the raising of the American flag over Chapultepec Castle.

Contrasting reactions. While American servicemen largely approved of the executions as just punishment for treason and a deterrent, Mexicans viewed the acts as barbaric vengeance. Mexican officials and citizens expressed horror, calling it an "atrocious act" and a "terrible slaughter," further fueling anti-American sentiment.

6. John Riley's Controversial Fate and Post-War Life

Riley was the greatest artillerist of the day, and we had suffered greatly on his account.

Reprieve from the gallows. John Riley, the charismatic leader of the San Patricios, narrowly escaped hanging. His death sentence was commuted by General Scott because he had deserted before the official declaration of war, making him subject to a lesser penalty under the Articles of War. This decision angered many American soldiers who saw him as the principal instigator of defection.

Branding and imprisonment. Instead of death, Riley endured 50 lashes and was branded twice with the letter "D" on his cheeks. He was then imprisoned, first in Acordada prison and later in Chapultepec Castle, alongside other San Patricios. During his imprisonment, he maintained contact with British consular agents, seeking assistance to return to Ireland.

Continued service in Mexico. After his release in September 1848, Riley was reincorporated into the Mexican infantry, serving with the permanent rank of major (brevet colonel). He was stationed in Veracruz and later Puebla, where he continued to face financial hardship and even accused local authorities of denying him justice after a robbery. His pay records show inconsistent payments and significant amounts owed to him by the Mexican government.

Return to Ireland. The last official record of John Riley in Mexico is his honorable discharge from the Mexican army in the summer of 1850, due to "service disability." He was discharged to Veracruz, likely to facilitate his return to Ireland. Despite later myths of a lawsuit against the U.S. government or a wealthy marriage in Mexico, strong circumstantial evidence suggests he left Mexico, disappearing into historical obscurity in his homeland.

7. The San Patricios' Enduring, Contrasting Legacies in Mexico and the U.S.

With medals, memorial plaques, annual ceremonies, and public schools honoring them, clearly the San Patricios are treated as heroes in Mexico.

Mexican heroes and martyrs. In Mexico, the San Patricios are revered as heroes and martyrs who sacrificed their lives for the nation's cause. Their story is celebrated through:

• Memorials: A prominent marble plaque in San Angel, Mexico City, lists the names of 71 San Patricios, commemorating them as martyrs.
• Annual ceremonies: Twice a year, on September 12th (anniversary of the hangings) and Saint Patrick's Day, colorful ceremonies are held, attended by civic officials, military units, and Irish diplomatic personnel.
• Public recognition: Schools are named after the battalion, and commemorative medals have been issued, perpetuating their heroic image in popular culture and official histories.

U.S. traitors. In stark contrast, North Americans have consistently regarded the San Patricios as traitors. Their actions are seen as a betrayal of their oath and country, and their punishment is generally viewed as justified. The story of the battalion is largely unknown or, when mentioned, often presented with factual inaccuracies, reinforcing the negative perception.

Myths and realities. The narrative surrounding the San Patricios is heavily influenced by myths and misinformation:

• Irish composition: The belief that the battalion was entirely Irish is false; only about two-fifths were from Ireland.
• Desertion timing: Many deserted much later in the war, often just weeks before their capture, not all at the outset on the Rio Grande.
• Post-war fate: Stories of Riley's lawsuit or wealthy life in Mexico are fabrications; he likely returned to Ireland.
• Martyrdom: Not all listed on memorials died for Mexico; some had sentences commuted or were American martyrs.

A complex tragedy. The story of the San Patricios is a complex tragedy, not a simple romantic tale. It highlights the plight of bewildered young men from diverse backgrounds, often driven by a combination of harsh military conditions, economic opportunism, and religious appeals, who made a fatal choice to switch allegiance in a brutal war.

8. The Mexican-American War's Profound Impact on Both Nations

The Mexican War made the United States a continental power stretching from the Atlantic to the Pacific.

U.S. expansion and military growth. The war had a transformative impact on the United States, solidifying its continental reach. The Treaty of Guadalupe Hidalgo ceded over half a million square miles of Mexican territory, leading to:

• Territorial gains: Expansion from the Atlantic to the Pacific, including California and New Mexico.
• Economic boom: Discovery of gold and silver in new territories.
• Military professionalization: The war served as a training ground for future Civil War leaders and boosted support for the U.S. Military Academy at West Point.

Internal divisions. Despite military triumphs, the war was deeply divisive within the U.S., exacerbated by the slavery issue and partisan politics. Many citizens questioned its justification, viewing it as aggression or a plot to expand slavery, leading to significant dissent and a lasting sense of war guilt.

Mexican devastation and resentment. For Mexico, the war was a series of profound tragedies, leaving a lasting scar on the national psyche. The consequences included:

• Massive losses: Thousands of military and civilian deaths, orphans, widows, and cripples.
• Economic ruin: Disruption of trade, decline in agricultural and industrial production.
• Political chaos: Frequent changes in government, insurrections, and a shattered faith in democracy.
• Territorial humiliation: The loss of vast lands, coupled with the occupation of their capital, engendered a deep and enduring resentment towards the United States, a sentiment that persists to this day.