For centuries, prisoners in the United States were housed together regardless of their citizenship status. That changed in 1999 when the federal government began to send noncitizens into separate prisons. Today, tens of thousands of people — more than half of all noncitizens in federal prison — live in an institution segregated by citizenship. The vast majority of these people are Mexican nationals. Nearly all of them are Latino.

The rise of the all-foreign prison raises pressing questions about federal immigration power and noncitizens’ equal protection rights. Yet no legal scholarship examines these unusual institutions. Few even know they exist. Drawing on extensive data from the Bureau of Prisons, internal agency documents, interviews, and other primary sources, this Article provides the first account of the all-foreign prison. It notes that these prisons are insulated from meaningful judicial review by an alienage jurisprudence that affords deference to any federal policy characterized as migration control. And it critiques this doctrine, arguing that courts need a more coherent and defensible conception of the relationship between national sovereignty and noncitizens’ equal protection rights. To that end, this Article advances a simple claim: only core immigration activities — setting rules on entry, exit, and naturalization — should count as migration control. Other species of state action, including segregating foreign national prisoners, may affect where and how immigrants live their lives. But they are not the kind of migration control that warrants deference from federal courts.

From Emma Kaufman, Segregation by Citizenship, Harvard Law Review, March 2019