Here is a historical work connecting the anti-slavery movement in early America to liberal Protestant theology, Slavery and Sin: The Fight Against Slavery and the Rise of Liberal Protestant (OUP 2011), by Molly Oshatz (San Francisco State University).  The publisher’s description follows.

In this groundbreaking examination of the antislavery origins of liberal Protestantism, Molly Oshatz contends that the antebellum slavery debates forced antislavery Protestants to adopt an historicist understanding of truth and morality.

Unlike earlier debates over slavery, in antebellum America the key question was whether slavery was a sin in the abstract. Unable to use the letter of the Bible to answer the claim that slavery was not a sin in and of itself, antislavery Protestants argued that biblical principles required opposition to slavery and that God revealed slavery’s sinfulness through the gradual unfolding of these principles. Although they believed that slavery was a sin, antislavery Protestants’ sympathy for individual slaveholders and their knowledge of the Bible made them reluctant to denounce all slaveholders as sinners. In order to reconcile slavery’s sinfulness with their commitments to the Bible and to the Union, antislavery Protestants defined slavery as a social rather than an individual sin. Oshatz demonstrates that the antislavery notions of progressive revelation and social sin had radical implications for Protestant theology.

Oshatz carries her study through the Civil War to reveal how emancipation confirmed for northern Protestants the notion that God revealed His will through history. She reveals how, after the war, a new generation of liberal theologians drew on this experience to respond to evolution and historical biblical criticism. Slavery and Sin provides critical insight into how the theological innovations rooted in the slavery debates came to fruition in liberal Protestantism’s acceptance of the historical and evolutionary nature of religious truth.