The vast majority of people incarcerated in the U.S. – counting all prisons, jails, youth and immigrant detention centers, and more – are held in state prisons and local jails, according to the Prison Policy Initiative's annual tally of America's mass incarceration sources. And, of those in state prisons, more than half have been convicted of violent offenses. And so the dominant national conversation about criminal justice reform, with its focus on federal legislation affecting only federal law and prisons, or concerned with drug offenses and other low-level crimes, misses the center of the target by a wide margin. 

That the states have driven a 500% increase in incarceration in the U.S. over the past 40 years is no secret among the analysts and state legislatures that have wrestled with state incarceration rates for at least the past 15 years. As it turns out, some of the states that have been most creative about lowering their incarceration are red states, mainly in the South, where politically conservative advocacy groups like Right on Crime have pushed for criminal-justice reforms for many years. Of course, it also makes mathematical sense that the locus of reform exists in the region that hosts some of the world's highest incarceration rates to begin with. Nationwide incarceration levels have slowly dropped to 1995 levels from their peak in 2008, but the decline pales in comparison to the drop in crime, which has fallen by more than half since peaking in the early 1990s.  Still, as this collection shows, progress has been made where policymakers have questioned assumptions about who should go to prison and for how long. 

• Oklahoma perennially flirts with the top of the incarceration-rate charts, so we have a before-and-after set of snapshots as that state grappled with solutions: my own story on why a first round of reforms foundered, and Cary Aspinwall's later look at the making of an unusually large release of people from the state's women's prison. 
• During that debate in Oklahoma, Justin Wingerter reported on how neighboring Texas became the pioneer in red-state sentencing reform. 
• Casey Leins looked at how Mississippi reduced its prison population by 11%, and why legislators faced up to the reality found in crime research that the severity of sentences has little effect on crime. 
• Tina Rosenberg looked at a program that changes hearts and minds at the critical decision point on the road to prison: local prosecutors' offices.