This weekend marks the 150th anniversary of the ratification of the Thirteenth Amendment. In his new book,Lincoln and the Thirteenth Amendment (Southern Illinois University Press, 2015), Boston College alumnus Christian G. Samito examines how Lincoln’s opposition to amending the United States Constitution shaped his political views before he became president, and how constitutional arguments overcame Lincoln’s objections, turning him into a supporter of the Thirteenth Amendment by 1864. Well into his presidency, Lincoln argued that emancipation should take place only on the state level because the federal government had no jurisdiction to control slavery in the states. Between January 1863 and mid-1864, however, Lincoln came to support a constitutional amendment to abolish slavery because it worked within the constitutional structure and preserved key components of American constitutionalism in the face of Radical Republican schemes. Samito’s previous publications include Becoming American under Fire: Irish Americans, African Americans, and the Politics of Citizenship during the Civil War Era. Read the introduction to Lincoln and the Thirteenth Amendment.