The U.S. prison population is booming. It is estimated nearly 2.2 million people were incarcerated in America in 2016, and as many people in the U.S. have criminal records as have graduated from four-year colleges.

Journalist and Yale Law lecturer Emily Bazelon attributes America's high incarceration rates to prosecutors more than judges. She says that in the 1980s, when crime was on the rise, legislators across the country passed laws with mandatory minimum sentences that have disproportionately affected black and brown communities.

"That set up prosecutors to be able to determine the punishment by the charge they bring in," Bazelon says. "And so we're still living with that change — even though crime has really fallen since that time."

Bazelon notes that the majority of court cases — more than 90 percent — end in a plea bargain rather than a trial, which gives prosecutors even more power.

"You see this kind of haggling over plea bargains in the hallway, not an open court," she says. As for a defendant's guilt and innocence? "Honestly, people don't even really talk about those things."

Bazelon spent 2 1/2 years reporting on the Brooklyn district attorney's office. Her new book, Charged, examines the power of prosecutors and looks at alternatives to bail, plea bargains and incarceration...

On how prosecutors' focus on winning convictions is linked to mass incarceration

We put prosecutors in this arguably difficult position. We tell them that it's their job to win convictions. We also tell them that they are obligated to be ministers of justice. Good prosecutors know how to balance those ethical responsibilities, but it's not always easy to curb your instinct to win. And so I think when prosecutors abuse their power, what we're seeing is a real tension in this dual nature of their role.

Charged
The New Movement to Transform American Prosecution and End Mass Incarceration, by Emily Bazelon