In this brilliant new look at the destruction of slavery during the American Civil War, Oakes reveals how the U.S. abolitionist movement relied not only on high-minded moral suasion but also on the small-bore legalistic strategy of the Republican Party. The party’s legal minds argued that although slavery was a state institution, and therefore the federal government could not interfere with its legal status in the states, the U.S. Constitution did not recognize slavery in federal jurisdictions -- in the territories and on the high seas, for example. They also maintained that slaves did not represent a collective legal caste, but rather that slaveowners had claims only on the services of particular individuals. As “property” in service, slaves could be legally “confiscated” in wartime as a military necessity -- a strange way of justifying emancipation, to be sure, but one that allowed the Union to free slaves under existing law even before the 1863 Emancipation Proclamation. Legal thinking continued to shape abolition even after the war, when a fear that Southern states would simply re-legalize the practice led Republicans to push for a constitutional amendment to ban it forever.