Reforming America's criminal justice system has long been a priority for Barack Obama. In The Audacity of Hope, written a decade ago, Obama lamented the "black men filling our prisons" and bemoaned how the "stigma of a prison record" can make it all but impossible for ex-felons to find employment. He complained about employers that "aren't willing to take a chance on ex-felons, and [that] those who are willing are often prevented from doing so." Obama even offered some ideas about how the public and private sectors could work together to "kick-start a transformation of circumstances for" ex-felons.

Over the last decade, Obama hasn't done very much to advance the cause of criminal justice reform. But that changed this week. In a series of events, the president highlighted the need for reform and pushed for action from a Congress that now seems ready to act.

On Monday, the president commuted the sentences of 46 people in federal prison for nonviolent drug offenses. On Tuesday, at the annual NAACP National Convention, he called on Congress to pass legislation to reform federal sentencing laws. And on Thursday Obama visited the El Reno prison in Oklahoma, becoming the first sitting president to visit a federal penitentiary.

In his speeches and remarks this week, Obama mentioned a wide array of reforms — from the elimination of mandatory minimum sentences and the end of voting prohibitions for convicted felons to limiting the use of solitary confinement and restoring proportionality to drug-crime sentencing.

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The president also called for a transformation in the way our prison system is viewed. Prisons, he said, should focus more on rehabilitation than on punishment.

The president isn't the only one taking up reform. The House Oversight and Government Reform Committee this week spent two days examining the criminal justice system. At a congressional hearing on Tuesday, Rep. Jason Chaffetz, R-Utah, noted that federal prisons make up a quarter of the Justice Department's budget and that that share is on pace to rise to one-third in five years.

Several weeks ago, a bipartisan coalition in Congress introduced the SAFE Justice Act, which contains numerous measures that would incorporate successful state criminal justice reforms into federal law.

In the past, when politicians talked about crime and punishment, they usually focused on the latter. Today, in a striking change, Democrats and Republicans alike mostly talk about what they can do to make conditions better for prisoners. As The New York Times put it this week, "What was once politically unthinkable has become a bipartisan venture."

Related: White House: Stay tuned on reports of Obama freeing dozens of drug-offenders

Criminal justice reform is a rare issue that can bring conservatives, liberals and libertarians together. As Obama said this week, "Even now, when — let's face it — it seems like Republicans and Democrats cannot agree on anything, a lot of them agree on this."

Anytime you see President Obama and the ACLU on the same side of an issue as Rand Paul and the Koch brothers, you know something special is happening.

Democrats can appear downright conservative in talking about the financial and moral costs to the country of our current criminal justice system. Meanwhile, conservatives and libertarians like Paul can sound like liberals in talking about how "tough on crime" policies have disproportionately hurt minority communities.

It's clear that reform is needed. Under the "tough on crime" policies of the past few decades, the federal criminal code rose from 3,000 crimes to 5,000 crimes. That led to less crime but a five-fold increase in the prison population, to 2.3 million. And as Obama often reminds audiences, it costs $80 billion a year to keep all those people incarcerated.

Obama and other reform advocates often tell audiences that the U.S. accounts for 5 percent of the world's population and houses 25 percent of its prisoners. That's a damning statistic, and one that seems at last to be prompting some action.

Daniel Allott is deputy commentary editor for the Washington Examiner