President Trump has invoked the theory that the U.S. is being “invaded” by immigrants at the southern border to curtail immigrants’ civil rights, deploy the military against noncitizen civilians, and expand his executive power. This Essay provides the first study of the origins of the immigration as invasion theory, tracing its emergence alongside the nineteenth-century Nativist political movement and burgeoning interest in pseudoscientific racial sorting. The immigrant invasion theory, this Essay argues, began with mid-nineteenth-century anxieties about the arrival of non-Anglo-Saxon immigrants and peaked with the reaction to Chinese immigration at the end of the nineteenth century. Politicians exploited fears of a “Mongolian invasion”—characterized as a high-volume takeover of unassimilated foreigners threatening public health, public safety, and the country’s cultural and racial purity—to justify building the punitive, carceral pillars of the modern immigration system.
This Essay proposes two constitutional inferences from the historical origins of the immigrant invasion theory. First, the term invasion was not applied to immigration until the mid-nineteenth century which, from an originalist perspective, undermines Trump’s invocation of an “invasion” under Article IV, Section 4. Second, the roots of the immigrant invasion theory in Nativism, religious and ethnic exclusions, and anti-Asian rancor carry equal protection implications. The Supreme Court has explicitly repudiated certain discriminatory regulatory traditions—including other historical practices stemming from nineteenth-century Nativism, xenophobia, and religious discrimination—based on their tainted legacies, indicating that the Court could reject Trump’s invasion theory because it is, to borrow Justice Thomas’s phrase from Mitchell v. Helms, “born of bigotry.”
Author
Skadden Fellow at the Mabel Center for Immigrant Justice. I would like to thank Professor Philip L. Torrey and Professor Jesse Hoffnung-Garskof for their generous guidance.
Copyright 2025 by Tamara Shamir
Cite as: Tamara Shamir, “The Greatest Invasion in History”: The Nineteenth Century Nativist Theory Behind Trump’s 2025 Immigration Agenda, 120 Nw. U. L. Rev. Online 114 (2025), https://scholarlycommons.law.northwestern.edu/cgi/viewcontent.cgi?article=1361&context=nulr_online.