What happens to people when we don't lock them up? What happens to society when we don't lock criminals up? Paul Butler wants to find out.

Prof. Butler, a Georgetown University law professor and MSNBC legal analyst, was on campus last week as the Criminal Justice Graduate Student Association's annual John S. Goldkamp featured speaker. A former federal prosecutor and a race and criminal justice scholar, Prof. Butler wants to see how close the United States can get to completely eliminating prison sentences while substituting them with something else. He dubbed this goal "prison abolition," a term one criminal justice graduate student said might sound scary to some.

"Abolition is a strong term," agreed Prof. Butler. "As a strong term, I think it has some power and some resonance as an organizing tool. When I talk about abolition versus reform—we didn't talk about reforming slavery, we talked about abolishing it. When we talked about the old Jim Crow, we didn't talk about reforming it, we talked about abolishing it. So I think when we talk about the new Jim Crow, we have to talk about abolishing it."

Continuing, however, he admitted that the term might scare some people. But Prof. Butler had come prepared with some interesting statistics to make his case that the prison system isn't keeping society as safe from violent criminals as some might hope:

• Ninety-five percent of those imprisoned are eventually released.
• Forty-six percent of violent criminals never even go to prison (the other 54 percent are either never caught, never prosecuted or never convicted).
• The average prison term for convicted murderers is only around 12 years.
• Despite this, the U.S. has about four percent of the world's total population while being home to about 22 percent of the world's prison population.

Prof. Butler admitted that violent crime has decreased in the U.S. since mass incarceration's rise in the '80s. But violent crime has also decreased globally during this period, and most other countries don't lock their people up at the rate the U.S. does. Increased incarceration is thought to have been responsible for only about a seven percent decrease in crime, and it's believed that there are diminishing returns here, and it may even eventually cause crime rates to increase.

"We shouldn't assume a strong correlation between the number of people who are locked up and the crime rate, and we certainly shouldn't assume a causation," said Prof. Butler. "But I get that abolition still seems scary because it raises the specter of all these criminals running around freely."

Further, he said, abolition is probably politically impossible at this particular juncture in time. But Prof. Butler is hopeful about the future of his cause. Libertarians, he said, worry about the "over-criminalization" of Americans. Fiscal conservatives want to end the cost of mass incarceration. And democratic socialists are concerned over issues of race and class inequality.

To that last point, Prof. Butler explained that prison itself was once a liberal reform. Philadelphia's own Eastern State Penitentiary was originally created to move the state away from more violent punishments (execution, whipping, hard labor).

"So that's progress," said Prof. Butler. "It's not a total upwards trajectory, as you know. We still treat some criminals by injecting poison into their veins or sitting them in an electric chair, but that's not how we treat most criminals."

Prof. Butler ventured a guess that prisons will eventually be replaced with some sort of "e-carceration" system. But with any type of lockup, noted a criminal justice graduate student, there remains the stigma of having a criminal record and being disenfranchised even after finishing a sentence.

Prof. Butler responded with questions of his own: "Is mass incarceration the disease? Or is it just a symptom of the disease?"

Believing it only to be a symptom, the professor stressed the need to spend tax money not just on rehabilitation, but also on social and educational programs for high-poverty communities with easy access to guns and gun violence. Doing so is expensive, so Americans will have to decide if actually being safer is more important than just feeling safer while saving money.