Clash of Extremes takes on the reigning orthodoxy that the American Civil War was waged over high moral principles. Marc Egnal contends that economics, more than any other factor, moved the country to war in 1861.

Drawing on a wealth of primary and secondary sources, Egnal shows that between 1820 and 1850, patterns of trade and production drew the North and South together and allowed sectional leaders to broker a series of compromises. After midcentury, however, all that changed as the rise of the Great Lakes economy reoriented Northern trade along east-west lines. Meanwhile,...