This Article examines the resources available under American law to address the issues raised by extraterritorial enforcement of one of the most widely recognized human rights—to be free from physical coercion and the loss of liberty. Part I reviews the history of adoption, interpretation, and enforcement of the Thirteenth Amendment. The scope of the Amendment gradually expanded through the joint efforts of Congress and the Supreme Court, resulting in a prohibition that now goes beyond involuntary servitude to all forms of peonage, whether supported by state or private action. Part II then looks to other sources of congressional power—the Commerce Clause, the Define and Punish Clause, and the Treaty Power—and analyzes how these clauses interact with the power to enforce the Thirteenth Amendment. These sources of congressional power are subject, at most, to the minimal constraint that any resulting law regulate activity that has something to do with the United States— that American law have something to do with actions or effects within this country, as seemingly required by the Due Process Clause of the Fifth Amendment. Taken together, the powers of Congress give it ample scope to enact any law realistically designed to prevent or remedy slavery overseas. Part III then looks at slavery in the modern world and examines how far it extends beyond historic forms of chattel slavery to other coercive and oppressive conditions of employment. As periodic reports by international organizations make clear, these now include a variety of forms of forced labor and human trafficking. Whether prohibitions against slavery should extend further to reach labor conditions that would not be tolerated in this country turns out to be a practical question of law enforcement and foreign relations, rather than a question of congressional power. The Article concludes with a brief discussion of the choice between narrower and broader efforts to enforce prohibitions against slavery overseas.