In this seminar we will study the constitutional history, meaning, and consequences of American territorial expansion in the nineteenth and twentieth centuries. From the Northwest Territory to Guantanamo Bay, critical constitutional debates have shaped the acquisition, governance, and disposition of territories annexed or otherwise controlled by the United States. We will take up this important area of American legal history, examining the constitutionality of the Louisiana Purchase, slavery and the annexation of Texas; the annexation of colonies (the Philippines, Puerto Rico, Guam, and others) during the imperialist period beginning in 1898; and the quest for self-determination in twentieth-century U.S. territories such as Puerto Rico, Guam, and the Northern Marianas. We will investigate the legal doctrines developed in the context of American expansion and empire by courts, but we will not focus solely on doctrine; we will look also at constitutional discourse and decision-making by the other branches of government and by the public. One of our aims will be to learn about and develop skills involved in the study of history, and to that end, weekly readings will include primary documents as well as secondary sources. Students will be required to write several think-pieces in response to the readings, as well as a final paper.