In 1890, the Supreme Court called solitary confinement "barbaric," speculating that it would be abandoned altogether as a correctional practice. But now, nearly 130 years later, it's clear that their prediction couldn't have been more wrong. Professor Keramet Reiter tells the story of how solitary confinement became so widespread in the US, what this practice means for prisoners, and what can be done to change the system.

For more on this topic:

• Check out Reiter's book, 23/7: Pelican Bay Prison and the Rise of Long-Term Solitary Confinement
• Read her SSN brief, The Root of America's Over-Use of Solitary Confinements in Prison — and How Reform Can Happen
• Listen to her interview on NPR's Hidden Brain podcast