By Ahilan Arulanantham
When can the government imprison people without trial? That question lurks beneath many important civil rights issues of our time, from the federal government’s plans to jail and deport millions of non-citizens under the immigration laws, to the indefinite detention of people convicted of sex offenses, to the confinement of unhoused people in major American cities, and, most recently, the plan to summarily jail and deport “alien enemies” on national security grounds. All of these involve forms of preventive detention—that is, imprisonment without trial to protect the public.
Under current doctrine, the legality of preventive detention schemes is governed by a substantive due process framework that requires courts to balance society’s interest in safety against the detained individual’s interest in liberty. Although litigators, judges, and scholars often disagree about how to apply that framework, they have all generally assumed that it does apply.
But that framework is a modern invention. Prior to World War II, the law took a very different approach to evaluating imprisonment without trial: the state could not preventively detain to stop conduct that could be punished under criminal law. That framework reflected a basic normative constraint—that preventive detention should not be used to circumvent the criminal legal system. If the conduct the state wanted to stop could be punished, the state was required to use the criminal law, rather than displacing it with a bespoke regime lacking the criminal law’s procedural and substantive protections.
That bedrock constraint began to erode during the Japanese American mass incarceration of World War II, and then disappeared over the next several decades as the Supreme Court upheld the preventive detention of non-citizen Communist Party members and then the pretrial preventive detention of people charged with federal crimes. Since then, state power to imprison people outside the criminal legal system has grown rapidly in new ways, as the due process balancing framework has proven malleable enough to legitimate nearly every preventive detention scheme that governments have created. As the federal government’s recent invocation of the “Alien Enemies” Act illustrates, more may soon be on the way.
In this Article, I uncover the origins of the common law doctrinal framework governing preventive detention, and then tell the story of its downfall, describing how today’s due process balancing framework took its place. I then draw lessons from that doctrinal history for our present moment, as scholars, policymakers, litigators, and courts seek to chart the limits of preventive detention authority in the face of new demands for expanded state power.
73 UCLA L. Rev. ___ (forthcoming), UCLA School of Law, Public Law Research Paper No. 26-07
