The Hamilton Project is an economic initiative put together by the Brookings Institution, an American non-profit think tank that is, “devoted to independent research and innovative policy solutions”.

Earlier this month, the Hamilton Project published a memo highlighting the economic costs crime and imprisonment have on our country. The memo found that while the crime rate has dropped by 45% since 1990, incarceration rates have more than doubled, rising by 222%.

The memo also found that for an African-American man who dropped out of high school, the chances of ending up in prison are a whopping 70%, compared to just 15% for similarly educated white men.

The memo also pointed out that per-capita, the U.S. incarcerates more people than any other country in the world and,

“imprisons at a rate six times greater than most peer nations, including those of the European Union, Japan, Israel, and Mexico.”

The Harvard Gazette recently discussed the Hamilton Project’s findings with Ronald S. Sullivan Jr., Harvard Law professor and director of Harvard Law School’s Criminal Justice Institute.

One of the questions they asked was how the crime rate and incarceration rate in the U.S. could be moving in such drastically different directions. His answers were not only knowledgeable but powerful and revealing.

Here’s an excerpt from the interview (I’ve bold-faced a few sections that I feel are particularly important):

GAZETTE: According to the memo, while the overall crime rate fell 45 percent between 1990 and 2012, the rate of imprisonment has spiked 222 percent between 1980 and 2012. What’s behind this disparity? Is that strictly the result of policy decisions like mandatory minimum sentencing, repeat-offender laws, and the growth in for-profit prisons? Or are other factors at work?

SULLIVAN: That’s certainly a big piece of it. … policy decisions in respect of mandatory minimums drive the huge incarceration rate. But there are other factors as well. What those factors are is the subject of a lot of academic debate nowadays. And to be honest, we’re not exactly sure what it is. We do know that on a per-capita basis the U.S. incarcerates more people than any country in the world, including Rwanda, Russia, Cuba, all of the places one does not associate with a robust tradition of liberty. And that’s in many ways shocking.

The theory would be … with the high rates of incarceration that the crime rate would go down and then that would be followed by less incarceration because there just wouldn’t be as many crimes committed. But those numbers have gone in opposite directions. Mandatory minimums simply don’t explain all of it. Part of it, at least I think, has to do with selective law enforcement — the over-policing of certain neighborhoods, particularly minority neighborhoods and poor neighborhoods. That is to say, if police are there and looking for crimes, and over-police certain neighborhoods, you’re going to produce more defendants in particular areas. And if the populations are drawn from poor populations, they’re unable to afford to be released on bail, they’re unable to afford good lawyers, and studies show that if you’re not released on bail you tend to stay in jail after sentencing. An unfortunate reality of the United States is that far too often the justice you receive is a function of how much money you have.

The prison-industrial complex is also an important factor. It doesn’t take an economist to know that if … you make your money by people going into prison, then there’s going to be higher incarceration rates. So I think that certainly plays a role as well.

GAZETTE: What are the areas of debate among scholars?

SULLIVAN: One explanation has to do with the United States’ articulated goals of punishment. Back in the ’70s and before, rehabilitation was an articulated goal of the criminal justice system. The Supreme Court has said clearly now rehabilitation is no longer a penological goal. We look at incapacitation, we look at deterrence, and we look at retribution as goals that the penal system serves. When you take rehabilitation out of the mix, then that de-incentivizes the system from having shorter sentences because there’s no longer an affirmative goal of reintegrating people meaningfully back into the community. That’s one of the things that scholars argue drive up the incarceration rate.

The other has to do with our system of elected judges in most states. Judges who are elected, the argument runs, respond to democratic pressures. We live in a political economy where people think that more and harsher punishment is better, even though most competent data suggests that longer sentences, after a certain point … make people worse as opposed to making them better. But you have democratically elected judges who respond to the will of the people, and if that will is for longer sentences, no matter how misinformed, then judges oftentimes acquiesce to those pressures.

The other issue has to do with legislators. It, again, has to do with the political economy in which we live. With this mantra of being “tough on crime,” legislators essentially race to see who can draft legislation with the harshest, longest penalties. I think that legislators don’t believe that prosecutors will attempt to enforce the most harsh provisions of particular laws, and in that sense, from the vantage point of the legislator, it’s sort of a win-win situation: They can get the political credit for drafting an incredibly harsh law, but not really have to deal with the effects because the notion is the prosecutor will sort it out and will recommend a fair sentence. That assumption, though, just hasn’t really been borne out in reality.

You can read a full transcript of the interview in the full story from the Harvard Gazette here.