President Obama tours a cell block at the El Reno Federal Correctional Institution in El Reno, Okla., on July 16. (Saul Loeb/Agence France-Presse via Getty Images)

John Pfaff is a professor at Fordham Law School.

This month, President Obama commuted the long sentences of 46 federal prisoners convicted of drug crimes, and over the next few days he laid out his vision for criminal justice reform in speeches to the NAACP and at the El Reno Federal Correctional Institution in Oklahoma. Prison reformers hailed these events as important steps forward in the effort to rein in the sprawling U.S. prison system.

I don’t think they should be so happy.

Obama’s speeches, unfortunately, explicitly emphasized one of the most problematic myths standing in the way of true penal reform, and the commutations implicitly did the same. In all three instances, Obama suggested that we can scale back incarceration by focusing solely on nonviolent offenders.

Obama made this a key point in his NAACP speech: “But here’s the thing: Over the last few decades, we’ve also locked up more and more nonviolent drug offenders than ever before, for longer than ever before. And that is the real reason our prison population is so high.”

This claim, which is widely accepted by policymakers and the public, is simply wrong. It’s true that nearly half of all federal inmates have been sentenced for drug offenses, but the federal system holds only about 14 percent of all inmates. In the state prisons, which hold the remaining 86 percent, over half of prisoners are serving time for violent crimes, and since 1990, 60 percent of the growth in state prison populations has come from locking up violent offenders. Less than a fifth of state prisoners — 17 percent — are serving time for nonviolent drug offenses.

And contrary to Obama’s claim, drug inmates tend to serve relatively short sentences. It is the inmates who are convicted of violent crimes who serve the longer terms.

Now, to be clear, not all violent offenses are especially harmful. But a significant fraction of those in prison for violent crimes are there for serious violence: murder, aggravated assault, armed robbery. Moreover, many officially nonviolent inmates have histories of violence.

In other words, for all the talk about nonviolent offenders, a majority of our prisoners have been convicted of a violent act, and even more have some history of violence. And because no one thinks we should set every drug or other nonviolent offender free, at some point we are going to have to reduce the punishments that violent offenders face if we really want to cut our breathtaking prison population down to size.

But this idea is a political third rail, and no leading politician has been willing to risk touching it. Almost all the reform proposals we have seen focus exclusively on scaling back punishments for drug and other nonviolent crimes.

That’s what made Obama’s commutations and policy speeches so disappointing. Incarceration is driven by so many local factors that neither federal sentencing reform nor presidential commutations can have much of an impact. What the president may be able to do, however, is use his national pulpit to shape the debate. Obama missed a major opportunity to influence the current conversation on how to reduce incarceration.

Imagine if Obama had signaled the importance of thinking about how we punish violent offenders by commuting the sentence of someone convicted of a violent crime, rather than repeatedly stating that all 46 inmates were nonviolent prisoners.

Imagine if he had used the occasions to explain to the nation why extremely long sentences, even for violent offenders, are generally counterproductive, by pointing out studies showing that such punishments do not really deter crime and that offenders pose less of a risk of recidivism as they enter their 30s and 40s.

Imagine if he had talked about how we could reduce our punishments for violent offenders without necessarily compromising public safety through improvements in policing or expanded access to drug treatment and mental health care.

But in Oklahoma, Obama declared he has no “tolerance” for violent criminals, who he said need to go to prison to keep our communities safe. That claim glosses over the important but difficult issues of exactly who counts as sufficiently dangerous to warrant incarceration and how long they should spend in prison.

I don’t want to seem churlish. A prison system with fewer nonviolent drug offenders serving long sentences would be a good thing. And the president did touch on several important points, such as the need to reduce the use of solitary confinement and the importance of thinking about how to help prisoners reintegrate into society after their release.

But if Obama had seized the opportunity to drive home the point that, sooner or later, we are going to have to confront how we handle violent offenders and the risks they pose, his speeches could have launched a difficult but necessary policy debate.

Instead, he played it safe. Worse than that, really. By focusing his actions and words on nonviolent drug offenders, he only strengthened people’s belief that we can reduce prison populations dramatically just by focusing on the “safe” cases. But we can’t.