An inside look at the most progressive candidate in a generation, who's poised to take on the most incarcerated major city in the US

• Civil rights attorney Larry Krasner is the heavy front-runner to win the race to be Philadelphia's next district attorney, a powerful position in the heavily incarcerated city.
• While he has never served in government, he has a long career of suing police for civil rights abuses and defending activists in court.
• District attorneys' races have become the frontline in the battle to reform criminal justice and end "mass incarceration," with millions of dollars being poured into local races over the last year.

Civil rights attorney Larry Krasner has always been obsessed with what it takes to make change. At the age of 11, he got into a debate with his Sunday School teacher about whether it was right to break the law for the greater good. The two were arguing over the Civil Rights movement and protests over the Vietnam War - events that shaped his life and perspective.

Today, Krasner is running for district attorney of Philadelphia, a powerful position in a city with the highest rate of incarceration of the US's 10 most populated cities.

At 56, he is pursuing elected office for the first time after a 30-year career defending radical activist groups like Black Lives Matter and Occupy Philadelphia. He's also sued police for civil rights violations more than 75 times.

"I was born in '61. So in '68 when I'm watching TV … I'm seeing the Vietnam War and the protests and the 1968 Democratic National Convention in Chicago," Krasner told Business Insider.

"I remember all that and, even more importantly, I remember [Martin Luther] King. … It was a very visual time, and when you are a 7- or 8-year-old kid and you're watching this happen ... it's compelling. The war was compelling. It was all compelling. And then, they were getting killed. [Robert F. Kennedy] was speaking out against the war. And then he is dead. And then King is dead, and he's dead because of white supremacists."

Krasner, well-dressed in a sharply cut blue suit, tinted horn-rimmed glasses, and a well-kempt head of silvery hair, doesn't look the part of a political outsider.

With his raspy but measured speech, he could pass for a senator in a liberal state. But make no mistake, Krasner may be the most progressive candidate for such a major office in years. The center of his campaign platform is ending "mass incarceration," the constellation of state and federal policies that have put more than 2 million Americans behind bars.

And though nearly all of the candidates in the seven-person Democratic primary he won in May promised reform, all it took was one look at their careers to convince him to run for office for the first time in his life.

Some of the candidates "were flagrantly authoritarian during their careers," Krasner said. "And yet all of a sudden I'm hearing about their 'Which way is the wind blowing now' virtues, and I just figured this is ridiculous."

"Somebody real has got to get into this, because these people aren't going to change anything."