What vexed [political scientist Michael] Fortner was that The New Jim Crow seemed to be two different books. One did a powerful job showing how mass incarceration undermines black communities and perpetuates racial inequality. The other — and this was the vexing part — advanced a political theory about how we got here. That history stressed the resilience of white supremacy. First came slavery; when slavery ended, a white backlash brought Jim Crow segregation; when Jim Crow crumbled, a backlash to the civil-rights movement spawned yet another caste system, mass incarceration. Each time, writes Alexander, an associate professor of law at Ohio State University, proponents of racial hierarchy achieved their goals “largely by appealing to the racism and vulnerability of lower-class whites.”

“I remember feeling like, where are the black folks in this story?” Fortner says. “Where are their voices? They’re constantly victimized. They’re not powerful. And then I thought…