By Yesenia Razo and Peter Schurmann
Nearly two centuries ago, a band of Irish emigres defected from the US military to join sides with Mexico in the Mexican American War. The San Patricios, or St. Patrick’s Battalion, have since become part of Mexican lore.
Rejecting the racism, religious intolerance and imperialism they found in the US, the San Patricios story remains a powerful indictment of US policy then and now.
“When we think about the cyclical border panics that we see about the U.S.-Mexico border, all that is a consequence of how this war was resolved,” Alexander Aviña told the Los Angeles Times in 2024. He added, “Or rather how it was not resolved between Mexico and the United States.”
Aviña, who teaches history at Arizona State University, was discussing the legacy of the several hundred Irish Catholic immigrants—estimates vary from 200 to 700—who fought for Mexico in a war of aggression launched by the US, one that resulted in Mexico ceding two fifths of its territory to its northern neighbor.
The historical parallels to Ukraine are hard to ignore, with US diplomats now pressuring Ukraine’s leaders to give up almost 20% of its territory to Moscow in exchange for ending a war started by Russia.
Equally hard to ignore are the echoes with the Trump administration’s ongoing mass deportation agenda largely targeting Latino immigrants. Much like depictions of the Irish more than a century ago, immigrants arriving from Latin America today are painted as “thieves, murderers and rapists,” rhetoric used to justify the administration’s inherently racist policies.
According to the historical narrative, the San Patricios were led by Irish native John Riley, who arrived in the US in the 1840s during the height of the Irish Potato Famine, which saw some two million Irish flee their homeland, many arriving on American shores.
Riley enlisted in the US military, where he and his fellow Irish soldiers encountered the anti-Irish and anti-Catholic hostility that was prevalent at the time across much of the country and mirroring the prejudice they sought to escape in England.
Just prior to the US decision to invade Mexico in 1846, Riley convinced a group of his fellow-Irish countrymen to defect to the Mexican side, where they found acceptance and camaraderie among fellow Catholics who, like in Ireland, were fighting off a larger, imperialist neighbor.
Riley went on to form the Batallón de San Patricio, which participated in some of the war’s bloodiest pitched battles. After the war ended in 1849, fifty members of the battalion were hanged as deserters by the US military, the largest such mass execution by US forces in history.
Surviving members would go on to integrate into Mexican society, starting businesses, raising families. Today, a bust of Riley stands in the Plaza San Jacinto in Mexico City, where the legacy of the San Patricios is celebrated every year on March 17, in commemoration of St. Patrick’s Day.
Here in the US, while that legacy has been all but forgotten, the hostility once directed toward Irish newcomers is now projected onto Latinos and other immigrants of color.
“If ICE were to walk into my work, I could definitely just blend in with the crowd,” Aisling, an undocumented Irish immigrant who has lived in Chicago for eight years, told CBS News.
Among an estimated 10,000 undocumented Irish immigrants currently living in the US, Aisling says she and other undocumented Irish she knows have grown more anxious as Trump continues to push for more deportations. But she acknowledges the ICE raids happening in and around her city are exclusively targeting communities of color, a policy she condemned as racist.
Meanwhile, Trump declared March Irish American Heritage Month, praising the Irish American community for “courageously overcoming adversity and hardship to embolden our culture, enliven our spirit, and fortify our way of life.”
Would that he could extend that same recognition to today’s immigrant community, which in 2022 contributed $75.6 billion in taxes, supporting businesses large and small, keeping US families fed, and keeping the US economy going strong, all while contending with an immigration system that by design forces them to remain largely in the shadows.
While St. Patrick today remains among the most celebrated of Irish saints, he was in fact born in what was then Roman Britain. He was, in other words, an immigrant who dedicated his life to Ireland, his adopted homeland.
Just as Riley and his band of San Patricios once stood against tyranny, today’s immigrants fight for their place in a land many share a deep historical connection to, one built on the labor of diverse peoples.
This St. Patrick’s Day, that history should be celebrated, alongside those who continue its legacy.
