University of North Carolina Press, 1997

No issue played a more direct role in the coming of the Civil War than the status of slavery in the federal territories. Territorial acquisitions more that tripled the size of the United States in the first half of the nineteenth century, and each addition of territory reopened debates over the nature of the Union and the revolutionary values of (white) liberty and equality that defined the republic and bound it together. White Americans identified expansion with a process of continued renewal in which the availability of cheap, fertile land created economic opportunities to achieve independence and protect individual freedoms. They also believed that slavery represented the utter negation of the liberty they so prized. But whites differed profoundly over their understanding of the relationship between black slavery and white liberty.