Nineteenth century American politician John C. Calhoun was unashamedly pro-slavery. So it may seem odd that A Disquisition on Government (1850), written in part to protect that practice, is so respected today. But South Carolina-born Calhoun was undoubtedly a great political thinker.

Calhoun—who served his country as senator, vice president, secretary of war, and secretary of state—believed that “majority rule” inevitably led to abuse of power. He proposed the principle of the “concurrent majority,” whereby minority groups would be able to veto central government legislation that worked against their interests. Calhoun believed this way politics would become more consensual, and the interests of minority groups would be protected.

The Disquisition became a rallying point for Southern statesmen and slave owners who claimed the federal government—dominated by Northern interests—ignored their rights. Ironically, the twentieth century saw civil rights activists and liberal thinkers latching on to Calhoun’s vision of the “concurrent majority” and proposing it as a means of driving a fairer democratic system for all minorities, including African Americans.