How does one obscure theologian born in the 1800s become the favorite philosopher of Barack Obama, the intellectual fuel for Martin Luther King Jr., the admiration of John McCain, and the inspiration for James Comey's secret Twitter handle? This deep dive cracks open one of history's most improbable intellectual legacies.

We trace Reinhold Niebuhr's journey from a young pastor in brutal 1920s Detroit to the architect of Christian realism, a framework that still shapes how politicians, activists, and ordinary people view power and human nature. Along the way we confront his uncomfortable contradictions on race, war, and faith, and discover why his hard-eyed view of human pride matters more than ever in a chaotic world.

• How Detroit's Ford assembly lines, the KKK's 20,000-member political machine, and World War I shattered his early ...