In July 1967, the city of Detroit was devastated by one of the most destructive race riots in American history. More than 500 people were killed or seriously injured, and 2,000 buildings were destroyed. The violence went on for five days, and peace was restored only when the city was physically occupied by the U.S. Army’s 82nd Airborne Division.

The burning of my hometown is my first memory. From our house on Harvard Road on the east side of the city of Detroit, I could smell the burning oil and see the federal troops. It was a blow from which the city never recovered; it went from a population of close to two million to one of about 700,000. My family was one of the hundreds of thousands who moved out of the city.

That loss marked me. Determined to do something about the causes of that riot and the social ills that followed – enduring racism and racial division, a plague of narcotics, and a terrifying crime rate – I returned to the city after law school and got an apartment near downtown. Within a few years, I got a job as a federal prosecutor and began the hard work of making criminal law work for the common good.

For the most part, I failed. We all did. Our efforts did not stem the flow of crack onto the streets and often exacerbated racial tensions. We solved few problems and perhaps caused more.

When I left prosecution for the academy in the year 2000, I changed my focus radically. I sought to define my vocation in a way that was consistent with my faith, transparent in operation, and actively engaged with the needs of the world.

I found the key to this new purpose within a riddle. I had often heard the directive of Micah 6:8 (“He has shown you, O mortal, what is good. And what does the Lord require of you? To act justly and to love mercy and to walk humbly with your God.”), but it did not make much sense. Within my field, criminal law, justice and mercy are in tension, after all. If justice is treating similarly situated people the same way, and mercy is to give some people grace, the two seemed incompatible.

Slowly, though, I realized that my new goal should be defined by that puzzle in two ways.

First, the directive to humility was clear. When justice and mercy are in play, the stakes are high. All of criminal law is tragedy. Within that tragedy, the lawyer is not, should never be, the most important person. The story is about others, and it is they who bear the greater burden.

The second directive is equally distinct. While I cannot reconcile the tension between justice and mercy, I can safely say this: If some part of the legal system is devoid of either justice or mercy, then it is not moral. Both must be present for a legal system to be legitimate.

That second conclusion has driven my scholarship and advocacy. There are many areas where mercy is shut out, and among them I have (with my students) concentrated on mandatory sentences, life sentences for juveniles, and the death penalty. On the other side, there is too little justice in our laws regarding abortion, and I have more recently come to address that issue as a pro-life advocate on CNN and as an academic at a symposium at Stanford. All of it, though, is framed by the wonderfully powerful Micah 6:8 and the riddle at its core.

A lot of what we did wrong as prosecutors was driven by mandatory sentences, which starve the system of mercy or individualized considerations. I taught at Baylor from 2000-2010, and started then to make this a focus of my work, particularly in relation to crack sentences, where the mandatory minimums and sentencing guidelines were particularly harsh. With my students there, I started to fight against those tough rules, and in the process became much more aware of the damage created by the laws I enforced. With one particularly heroic student, David Moore, we helped stop a series of wrongful prosecutions in a small town near Waco, a project that was the basis for the Samuel Goldwyn Films production American Violet. Will Patton played David in the movie (to perfection), and it had a profound effect on me – it properly portrayed my students as heroes, an insight that drove me to engage them more deeply in future projects.

One of those projects led to the Supreme Court, where I won a ruling (Spears v. United States, 2009), that trial courts could “categorically” reject the harsh sentencing guidelines that applied to crack offenses. To say “I” won, though, is less than true. Much of the work on that case was done by Dustin Benham, a student, who got to see his work very literally transform the law of the land. For a teacher, that is as good as it gets.

At St. Thomas, I have continued to advocate for an undoing of the mandatory crack laws. Over 5,000 federal prisoners still languish in prison under rules that have now been reformed, but were not made retroactive. They would be free if given the benefit of the law now on the books. My students and I have worked to change their fates – at both the retail and wholesale levels.

At retail, our new Federal Commutation Clinic works with individual prisoners to seek a commutation (reduction of sentence) from the president. Our students have done profound and important work – going to prison to meet the clients, developing their narratives, and submitting petitions for freedom on behalf of people they have gotten to know as individuals. At the wholesale level, I have pressed the President to grant a mass commutation to these prisoners through the press (MSNBC, Washington Times, and Huffington Post) and through a series of meetings with White House staffers and Washington activists who have embraced this idea.

In the area of juveniles sentenced to life in prison without the possibility of parole, progress has been made, as well. In 2009, with two students helping me, I testified before the House Judiciary Committee’s subcommittee on crime in opposition to the continued use of this sentence. Since then the Supreme Court has issued two rulings limiting juvenile life without parole, and several states have purged it from their law at the urging of my allies. Within Minnesota, we had a debate at St. Thomas on the issue in 2011, and discussed the issue on both radio and television in the area.

In the realm of merciless sentences, the death penalty is the defining issue. Since 2010, I have not only published a series of articles and book chapters, but have taken the faith argument to the pews in nine states through a variety of media and with the constant assistance of my colleagues, students, and a few intrepid collaborators. Most significantly, we have performed the trial of Jesus, a modern-day interpretation of Christ’s sentencing under contemporary state death-penalty laws.

In the trial, I serve as the prosecutor and Jeanne Bishop, a public defender from Chicago who came to death penalty advocacy after the murder of three of her family members, is the defense attorney. Students (including Sara Sommervold, David Best, and Phil Steger) are second attorneys and witnesses; their input has been transformative. The point of this project is to put into juxtaposition the audience members’ faith with their thinking on the death penalty. To drive that point home, the audience is divided into juries at the end of the trial and deliberate to a verdict. We have taken this project, without funding or an organizational sponsor, to 12 venues in nine states, in places as diverse as Chicago, Cambridge, Mass., and Jefferson City, Tenn. – from Regent University to Fuller Theological Seminary and Episcopal Divinity School.

Has this kind of advocacy mattered? Perhaps. When Illinois rid itself of capital punishment in 2011, Governor Quinn allowed me to make our arguments to his legal staff, made sure that Jeanne Bishop was present as he announced his decision, and insisted that she got the pen he used to sign that institution out of existence. In Austin and Oklahoma City and Richmond, minds have been challenged and changed. The experience has deepened and broadened my own faith, and I have walked away every time struck by the talents of our students.

That’s what we can do at St. Thomas – not just because of our talents or interests, but because of a community that embraces faith as important, nurtures people who challenge society from a position of faith, and encourages us to transform ourselves in the process. I plan to do more, and am grateful to my core for that rare opportunity. It is not only the fear of the fire next time that motivates me; but also the hope that those we teach surpass us even as we teach them.

Mark Osler is professor of law at St. Thomas Law School.

From Exemplars, a publication of the Grants and Research Office.