U.S. Immigration and Customs Enforcement (ICE) has detailed Mahmoud Khalil—a legal permanent resident with a green card and prominent student-activist-turned-negotiator in pro-Palestine demonstrations at Colombia University. Peter Markowitz, professor of law at Benjamin N. Cardozo School of Law and the founding faculty member and co-director of the Kathryn O. Greenberg Immigration Justice Clinic, offers legal analysis of the detention.