Ahilan T. Arulanantham

The Constitutional Question in Civil Detention

What does due process owe a person locked away where no one is watching? Inside immigration detention, confinement can settle into routine — the detainee has no lawyer, removal drifts without a date, a disability makes the hearing unintelligible. For most of American legal history, those conditions were treated as administrative facts, absorbed quietly by a machinery that calls itself civil and therefore owes less. Ahilan T. Arulanantham has spent a quarter century converting them into constitutional and statutory questions a court must actually answer.

The commitment has roots older than his career. Arulanantham's parents are Sri Lankan Tamil immigrants who left their country to escape discrimination and sporadic violence against Tamils; when civil war erupted in the 1980s, much of his extended family fled and resettled in Southern California, where he grew up in Lancaster, on the high desert edge of Los Angeles County. He took a degree from Georgetown, went to Oxford as a Marshall Scholar, earned his law degree at Yale in 1999, and clerked for Judge Stephen Reinhardt on the Ninth Circuit. An Equal Justice Works fellowship at the ACLU's Immigrants' Rights Project in New York followed, and then two years as an assistant federal public defender in El Paso, standing up daily in a border courtroom where immigration enforcement and criminal punishment blur into each other. By the time he joined the ACLU of Southern California, he had seen the system from nearly every angle at which a person can be crushed by it.

Nadarajah and Five Years of Detention

The case that announced his method was Nadarajah v. Gonzales. Ahilan Nadarajah, a Tamil asylum seeker who shared his advocate's first name, had won his asylum claim before an immigration judge — twice — and yet remained imprisoned for nearly five years without ever being charged with a crime. Arulanantham took the question to the Ninth Circuit and won a 2006 ruling that the government had no statutory authority to detain him indefinitely, ordering his release. The victory did more than free one man; it insisted that detention is not a default condition the government may maintain out of habit, but an exercise of power that must be justified, person by person, under law.

From there he built the detention docket that made his name. In Rodriguez v. Robbins, he won classwide relief in the Ninth Circuit requiring bond hearings for immigrants held in prolonged detention — a rule that gave thousands of people something they had never had: a moment when a neutral decision-maker had to ask whether their continued confinement served any purpose at all. When the case reached the Supreme Court as Jennings v. Rodriguez, Arulanantham argued it there twice across two terms, defining a constitutional question that continues to structure how courts examine prolonged detention.

Franco-Gonzalez and Appointed Counsel

The achievement that may last longest began with people the system had rendered invisible twice over. In Franco-Gonzalez v. Holder, Arulanantham and his colleagues represented detained immigrants with serious mental disabilities — people expected to navigate deportation proceedings they could not comprehend, alone, because immigration adjudication carries a civil label and therefore no right to appointed counsel. The litigation established the first federal right to appointed representation for a defined class of immigrants facing removal, backed by a continuing injunction and a system of screening and safeguards across several western states. The premise of the proceeding itself changed: a person unable to understand the case against him could no longer be expected to defend his liberty by himself.

That result — a structural transformation, not a one-time verdict — is characteristic. So is the range. In FBI v. Fazaga, Arulanantham stood before the Supreme Court on behalf of Muslim Americans in Orange County who had been surveilled by the federal government because of their religion, pressing the claim that national-security secrecy cannot swallow judicial review of religious discrimination. When the federal government moved in 2018 to end Temporary Protected Status for hundreds of thousands of long-settled residents, he became a lead architect of Ramos v. Nielsen and its successors, litigation that kept families of Salvadorans, Haitians, Nicaraguans, and others lawfully present for years while courts reviewed the government's actions. In April 2026 he returned to the Supreme Court lectern a fourth time, arguing on behalf of Syrian TPS holders in Mullin v. Doe.

The MacArthur Fellowship

In 2016 the MacArthur Foundation named Arulanantham a Fellow for leading legal efforts to secure due process for immigrants. California Lawyer magazine twice named him a Lawyer of the Year, in 2007 and 2013; the American Immigration Lawyers Association gave him the Arthur C. Helton Human Rights Award in 2010 and, with his litigation team, the Jack Wasserman Memorial Award in 2014 for excellence in litigation. He has testified before Congress three times on detention and due process. Over nearly twenty years at the ACLU of Southern California, he rose to senior counsel and legal director while building a record of major immigration-detention litigation.

Litigation and Teaching at UCLA

In 2021 Arulanantham carried the practice into the academy, joining UCLA School of Law as Professor from Practice and faculty co-director of what is now the Miñana Family Center for Immigration Law and Policy. The move subtracted nothing from the litigation; it multiplied it. He continues to argue the field's defining cases while training the lawyers who will inherit them, teaching students to read immigration law simultaneously as constitutional structure, statutory text, and immediate human stakes — having earlier taught at the University of Chicago and UC Irvine law schools. The center he co-directs has become a national engine of scholarship and litigation, a place where TPS cases and detention challenges are staffed by students learning that doctrine is something they build.

Due process, as Arulanantham litigates it, is concrete and testable: the person facing confinement must understand the proceeding, must be able to contest the government's position, and must receive a timely decision from a neutral adjudicator — or the custody cannot stand. It is a modest-sounding standard, and it has taken him to the Supreme Court four times, because the gap between that standard and the daily operation of immigration detention remains one of the widest in American law. He works in the gap. Harmonizing immigration law with constitutional law and basic human rights principles, as he describes the project, is not an abstraction; it is the difference between a hearing and a formality, between five years in a cell and a life resumed.