In 2015, New York announced it had reached a landmark settlement with the New York Civil Liberties Union, which sued over the state's aggressive use of solitary confinement to discipline inmates.

Five Mualimm-ak is one of the activists who pushed for the changes. He spent five years in solitary and says it left him broken.

"When people say you survived solitary? Nobody survives that," he says.

Gov. Andrew Cuomo, a Democrat, agreed to a multi-year process phasing in limits on the time inmates spend in isolation and improving conditions there. But in recent weeks, the New York State Correctional Officers & Police Benevolent Association has begun publicizing violent incidents where inmates assault prison staff. The powerful group says solitary confinement is a necessary tool that keeps prisons safe.

Union head Mike Powers argues the reforms are partly to blame for recent incidents. Without the threat of solitary confinement, he says, officers have less control. He cites state prison data showing the number of assaults on officers by inmates rose by a third over the last decade.

[For more of this story, written by Brian Mann, go to http://www.npr.org/2017/04/04/...-pushback-from-union]