Saint Patrick's Battalion: 50 Hanged, and the One Who Wasn't

A Recruitment Pitch From the Other Side

By the mid-1840s, close to half of the enlisted men in the U.S. Army's ranks along the Rio Grande were Catholic immigrants, mostly Irish and German, and the Army's own officer corps treated them accordingly. "Nativist" prejudice ran through the ranks: foreign-born soldiers drew harsher punishments than native-born Americans for identical offenses, and "bucking and gagging" — trussing a man and gagging him for hours — was a routine penalty for minor infractions. Of the roughly 40,000 U.S. regulars who served during the Mexican-American War, 5,331 deserted, nearly 13 percent of the force; of those, close to 1,000 were Irish-born and 445 were German, and close to 20 percent of the Irish soldiers who had enlisted went over the hill, according to historian Peter F. Stevens, author of the 1999 book The Rogue's March, writing for History News Network.

Mexico's government made a deliberate play for those men. Aware that Catholic immigrants filled nearly half of General Zachary Taylor's companies, Mexican officers circulated pamphlets urging Irish and German soldiers to abandon a war against a fellow Catholic country, offering land grants, higher pay, and citizenship to anyone who crossed over. John Riley, an Irish-born artillery sergeant who had served in the British Army before enlisting in the U.S. 5th Infantry at Fort Mackinac, Michigan, in September 1845, took the offer early: he deserted on April 12, 1846, swimming the Rio Grande after slipping away on the pretext of attending Catholic Mass, according to the Texas State Historical Association's account. That was not quite two weeks before the war's first military engagement, the April 25, 1846 skirmish at Rancho de Carricitos known as the Thornton Affair, and about a month before the United States formally declared war, a timing gap that would later save his life.

Riley organized fellow deserters and other foreign nationals into an artillery company under Mexican command, eventually named the Batallón de San Patricio after the patron saint most of its Irish members shared. The unit fought at Matamoros, Monterrey, Buena Vista, and Cerro Gordo, earning praise from Mexican commanders and, at Buena Vista, the War Cross for several of its men after an artillery duel that killed or wounded roughly a third of the company. By mid-1847, with Gen. Antonio López de Santa Anna's forces regrouping to defend Mexico City, the San Patricios were reorganized into a larger two-company battalion under Riley's command.

Churubusco: Where the Story Turned

On August 20, 1847, Santa Anna positioned the San Patricios, with a battery of cannon, at a fortified bridgehead and Franciscan convent at Churubusco, on the southern approach to Mexico City. Ulysses S. Grant, then a young lieutenant marching into the valley with Gen. Winfield Scott's invading army, later called Churubusco "about the severest battle fought in the valley of Mexico" — the same campaign that carried him into Mexico City that September, nearly fifteen years before he commanded armies of his own at Shiloh. A supply wagon's ammunition turned out to be the wrong caliber for every weapon in the Mexican lines except the San Patricios' own muskets, leaving them to hold the position with a fraction of the defenders while the rest ran out of ammunition and could not fight back.

When the position became hopeless, Mexican soldiers inside the convent tried three times to raise a white flag of surrender; each time, San Patricio members tore it down, aware that capture meant the gallows. Gen. Pedro de Anaya ordered his men to keep fighting "with their bare hands if necessary" after Captain Patrick Dalton tore down one of the flags himself. The position finally fell when U.S. Army Capt. James M. Smith raised his own handkerchief and accepted surrender following brutal hand-to-hand fighting through the convent's halls. Anaya's own battle report put San Patricio losses at 35 killed and 85 captured, including a wounded Riley — roughly 60 percent of the battalion's strength lost in a single engagement, according to the Saint Patrick's Battalion's Wikipedia summary of Anaya's account.

Two Courts-Martial, No Lawyers, No Transcripts

Scott issued General Orders 259 and 263, convening two separate courts-martial for the 72 San Patricios formally charged with desertion. Col. John Garland presided over the first at Tacubaya on August 23, 1847; Col. Bennet Riley, an Irish Catholic officer, presided over the second at San Ángel on August 26. Neither trial provided the defendants with legal counsel, and no transcripts were made of the proceedings, according to the Texas State Historical Association. Most defendants either offered no defense or had none recorded; a few claimed drunkenness had led them to desert, a common defense at the time that occasionally won lighter sentences, while others said they had been forced into Mexican service. Wealthy Mexicans visited the prisoners and came to their defense at trial.

Of the 72 men tried, the two courts-martial condemned all but two to death outright, sparing only one man for improper enlistment and one for insanity. Scott's subsequent review is what produced the final, lower count: issuing General Order 281 for the San Ángel group on September 8 and General Order 283 for the Tacubaya group days later, and responding to appeals from the archbishop of Mexico, the British minister, and foreign residents of Mexico City, Scott spared several more condemned men for their youth and one because he had been too drunk to know Mexican forces had effectively kidnapped him. Twenty of the San Ángel death sentences and thirty of the Tacubaya death sentences survived that review, fifty in all.

The Desertion Date That Saved John Riley

Under the Articles of War then in force, execution by hanging was reserved for men who deserted to the enemy during a declared war; those who left before a war began faced lashing, branding, or hard labor instead. Riley's desertion on April 12, 1846, came before the United States declared war on Mexico on May 13, so Scott ruled he could not be hanged, regardless of how much damage his artillery expertise had done to his former army. Some American officers wanted Riley executed more than any other prisoner, believing his skill and rank had driven the other desertions; Capt. George Davis later wrote that officers urged Scott "that it would be far preferable that every one of the rest of the deserters should be pardoned rather than that Riley should escape death." Scott held firm on the legal technicality.

Riley's actual sentence was fifty lashes and a letter "D" for deserter branded into his cheek, on top of an iron yoke he was ordered to wear for the rest of the war — a combination that itself exceeded what the Articles of War prescribed for pre-war desertion, according to Wikipedia's account of the sentencing. On September 10, 1847, Riley and six other prisoners spared the noose were stripped to the waist and bound to trees in the plaza at San Ángel. Stevens's account, drawn from eyewitness testimony, describes the officer overseeing the lashings losing count partway through and delivering 59 blows rather than 50, leaving Davis to write that the prisoners' backs looked like "a pounded piece of raw beef." The branding iron was applied upside down on Riley's first pass, searing his cheek a second time to correct it.

Fifty Hangings, Timed to a Flag

The first executions followed immediately, in the same plaza where Riley had just been lashed: 16 of the San Ángel group were hanged on September 10, 1847, with the remainder of that group's death sentences carried out within the following days. The Tacubaya group's 30 condemned men were held for the largest and most theatrical of the executions. On September 13, Col. William S. Harney marched them to a gallows on a hill at Mixcoac, within sight of Chapultepec Castle, where Scott's army was storming the fortress that guarded the final approach to Mexico City. Harney told the prisoners they would hang the moment the American flag went up over the castle, then left them standing bound and noosed for roughly four and a half hours while the battle played out.

When the count came up short — one condemned man, Francis O'Connor, had had both legs amputated the day before — the army surgeon told Harney the man could not stand. Harney's reply, recorded by witnesses: "Bring the damned son of a bitch out! My order was to hang 30 and by God I'll do it!" O'Connor was carried out on his stumps and hanged with the rest. At 9:30 a.m., U.S. troops raised the flag over Chapultepec, and Harney gave the order. He later refused to let the bodies be cut down, saying he had "no orders to unhang them," and was promoted to brigadier general not long afterward.

Fifty executions across the two trials makes the San Patricios' punishment the largest mass execution the U.S. military has carried out. It is not, however, the largest single-event hanging in American history: that distinction belongs to the 38 Dakota men hanged at Mankato, Minnesota, in December 1862 at the close of the Dakota War, a single mass hanging larger than either of the San Patricios' two execution dates on its own.

A History the Army Spent Decades Denying

For years after the war, the U.S. Army's standard response to outside inquiries about the San Patricios was that no such unit or records existed, an official position historians have described as a deliberate effort to discourage future desertion by erasing the story rather than publicizing it. That stance held until 1915, when an inquiry pushed by U.S. Representatives William Henry Coleman and Frank L. Greene forced the Army to acknowledge the battalion's history and turn its surviving records over to the National Archives.

Mexico took the opposite approach from the start and never stopped. The men are commemorated every September 12, the accepted anniversary of the executions; in 2002, Mexico's Congress inscribed "Defensores de la Patria 1846–1848 y Batallón de San Patricio" in gold letters on its Wall of Honor; and in 2004, the Mexican government gave a commemorative statue to Ireland, erected in Clifden, County Galway — Riley's own birthplace, which flies the Mexican flag each September 12 in his honor. The same hair's-width timing that spared Riley the noose shows up again and again in how wars are actually adjudicated after the fact: a battle fought after a treaty is signed can still count as legitimate if ratification hasn't happened yet, just as a desertion that happened before a war was declared could not legally be punished as treason during one. In both cases, the paperwork's exact timestamp, not the fighting itself, decided the outcome. Unlike Benedict Arnold, whose British paymasters distrusted him even while cashing in his betrayal and paid him a fraction of what he had demanded, the San Patricios who survived the war found a country that trusted them enough to keep granting them land and citizenship, and a government that has spent nearly 180 years since publicly honoring the fifty who didn't survive it. Emiliano Zapata, a later Mexican revolutionary, is remembered through a rebel motto that was already thirteen years old when he died.