Even though chattel slavery caused major fractures between the U.S. North and U.S. South, the U.S. West loomed large in the sectional crisis. Explain how the West played a role in 1840s and 1850s debates over slavery and in the Civil War. How did U.S. westward expansion affect the slavery debate? How did the West figure into political compromises around slavery? Why was the West the site of bloody conflict over slavery during the 1850s? What role did the U.S. West play in Union policies during the Civil War?