By William J. Stuntz, Harvard University Press, 432 pages, $35

Editors’ Note: This review was updated to reflect a Correction.

The United States is the world’s leader in incarceration with 2.3 million people currently in the nation’s prisons or jails—a 500 percent increase over the past 30 years. A country with only 5 percent of the world’s population manages to boast 25 percent of the world’s prison population.

Numerous academics, criminal law practitioners, and policy makers have written about the causes of mass incarceration in America. William Stuntz’s posthumous book, “The Collapse of American Criminal Justice,” manages to fill a gap in the literature on America’s zealousness to incarcerate by reaching back in time to explain early United States legal thinking and judicial precedent.

Stuntz walks the reader through the annals of criminal justice from an academic vantage point on how America lost its way in its often well-meaning yet misguided efforts to combat crime. A law professor at Harvard Law School, Stuntz died earlier this year at age 52.

He leaves us with an insightful book that will no doubt attract the attention of legal scholars, historians and those working in the criminal justice field.

Interwoven delicately throughout this work is the question of how we strike the right balance between punishing those who break moral codes and how we grant mercy to those whose actions do not justify punishment.

Somewhere along the way, our criminal justice system lost its morality and its purpose. William Stuntz’s “The Collapse of American Criminal Justice,” explores where and how that happened.

Stuntz blames many of America’s current criminal justice woes on the gradual abandonment of local democratic control. He laments that decision-making power should not have been handed over to legislators, appellate judges, and state and national officials. He yearns for the more egalitarian past when the criminal justice system relied on decisions of local jurors and the discretion of local judges, which was more common in the earlier years of our criminal justice system.

Stuntz points his finger at prosecutors for their role in the swelling prison population. He argues that prosecutors have replaced judges as the system’s key sentencing decision-makers, exercising their power chiefly through plea-bargaining. In an era in which 19 out of every 20 felony convictions are obtained by guilty plea, compared with roughly two-thirds as recently as the early 1960s, it is hard to ignore the validity of that premise. Without a jury of one’s peers weighing in on the decision as to whether or not incarceration is appropriate, the system loses transparency and mercy.

Lest we blame our own generation of lawyers, judges and legislators, Stuntz’s book takes a look back in time to the beginning of criminal law in America. He raises interesting legal questions about our country’s perpetual struggle to strike the right balance between procedural and substantive law.

In the past, substantive law was less clear, and this made jurors’ jobs more important in their ability to define crimes and apply their own definitions. Today’s criminal statutes are replete with expansive crime definitions, partly due to legislators who wish to be seen as tough on crime.

While meticulously researched and comprehensive regarding judicial and legislative decisions that led up to our nation’s incarceration “disaster” (a word Stuntz uses himself to describe the bloated prison population in America), Stuntz only devotes roughly six of the book’s 432 pages to a discussion of the draconian drug laws created in the 20th century. Given the book’s central theme that the system is broken, his discussion feels incomplete without further attention paid to the drug wars of the last few decades. However, Stuntz is quick to compare with insight the now defunct prohibition laws and today’s drug laws. During prohibition, addicts and causal drinkers were not transformed into criminals, as are their counterparts in drug cases today.

Stuntz does not ignore the fact that America locks up such a disproportionate number of young black men, but his reasons for their over-incarceration are a bit vague. One premise is that the justice system grew less egalitarian due to the Warren Court’s expansion of procedural rights for defendants. Instead of protecting poor defendants, the Court’s decisions simply paved the way for the rich to buy expensive counsel who could then make sophisticated procedural arguments.

Stuntz believes the Court’s expansion of criminal procedural rights as well as other more recent decisions such as the expansion of the confrontation clause added too much complexity to criminal law, making trials expensive, and, more importantly, less focused on the substance of the crimes themselves.

Stuntz does discuss the line of cases that now make racial discrimination impossible to prove, hence impossible for courts to remedy. He makes the same argument that Michelle Alexander did in her book “The New Jim Crow: Mass Incarceration in the Age of Colorblindness”: that these cases have resulted in a world where no matter how compelling the statistical evidence, proof of conscious, intentional bias is necessary to present a credible case of discrimination; a standard near impossible to prove.

In his last chapter, Stuntz finally offers solutions. A more perfect world would expand the number of jury trials; vagueness would be re-introduced into criminal law to give more discretion to judges and juries; similar to the concept of military court reviews, higher courts would review guilty pleas with great care; an entire line of Supreme Court cases that all but bar claims of discrimination against black crime victims would be overturned; and more police, especially those who practice community policing, would patrol the streets.

After reading this book, it is difficult to suppress the urge to start from scratch in building a criminal justice system that is fair, impartial and merciful. Yet through these rich pages, Stuntz gives us morsels of hope as well as tools to begin that re-building process.

Lauren-Brooke Eisen is a former prosecutor who works for a New York City-based nonprofit, where she focuses on criminal justice policy including writing about trends in legislation.