Mexicans have been migrating to the United States in large numbers since the early 20th century and over time the share classified as irregular has varied sharply depending on the social, economic, and political circumstances prevailing north of the Mexico-U.S. border. Here we unmask the reality that irregular migration is more of a socio-political construction than a well-defined legal category. Over time, the share of Mexicans classified as legal immigrants, temporary legal workers, or irregular migrants has varied widely. Since 2008, however, unauthorized migration from Mexico has waned and Central Americans have taken the place of Mexicans among those apprehended along the Mexico-U.S. border. Rather than being processed as asylum seekers, Central Americans being are criminalized as «illegal migrants» and sent into detention facilities to maintain the fiction of an ongoing «alien invasion» from south of the border. The repressive pressure directed disproportionately at Latin American immigrants can be expected to have far reaching consequences given that Latinos now constitute more than 18% of the U.S. population, 26% of all children aged five and under, and the vast majority of children living with parents in irregular status are native U.S. citizens.