In 2008, Calvin Bryant was a 20-year-old student at Tennessee State University. He had been a talented fullback in high school and dreamed of going pro.

Now he's serving 17 years in Tennessee state prison—15 of them mandatory—for a first-time, nonviolent drug offense. His sentence is substantially longer that it normally would have been under the state's drug laws, just because of where he lived.

Police arrested Bryant in 2008 for selling 320 pills, mostly ecstasy, out of his Nashville apartment to a confidential informant who'd been bugging him. Tennessee treats this as a serious offense under any circumstances: Normally he would have faced at least two and a half years in prison. But because Bryant lived in a housing project within 1,000 feet of an elementary school—roughly three city blocks—his sentence was automatically enhanced under Tennessee's drug-free school zone laws to the same category as rape or second-degree murder.

Indeed, as someone with no prior adult criminal record, Bryant would have been eligible for release earlier if he'd committed one of those violent felonies.

Bryant's case is now the subject of a legal challenge filed by the Tennessee attorney Daniel Horwitz. Horwitz will go before a state judge tomorrow to argue that the arbitrary and excessive nature of Bryant's sentence violates his rights under the Eighth Amendment, which prohibits cruel and unusual punishments.

It's also a case study in how police and prosecutors use drug-free school zones, which exist in all 50 states and are supposed to protect schoolchildren from drug pushers, to threaten drug offenders with huge sentences whether or not they were dealing to a minor and whether or not school was even in session at the time.

"There is no circumstance in which it makes sense to punish a first-time, nonviolent drug offender more harshly than a rapist or a murderer," Horwitz tells Reason. "Mr. Bryant has more than paid his debt to society, and as everyone who is familiar with his case has recognized, he deserves to be released."

That's not just the opinion of a bleeding-heart criminal defense lawyer. The prosecutor who put Bryant in prison, Robert McGuire, submitted an affidavit to the court along with Horwitz's petition.

"I fail to see how an additional six years of incarceration will improve Mr. Bryant's amenability to correction or would be required to maintain public safety," McGuire writes. "I additionally fail to see how his release at a time earlier than 2023—and after over nine years of incarceration—will deprecate the seriousness of the offenses for which he was convicted or significantly imperil public safety."

The 12 members of Nashville's city council have also signed a letter in support of Bryant's petition for sentencing relief.

Civil liberties and criminal justice advocates have long argued that the large radius of these zones create overlapping "superzones" that blanket urban areas, especially poor and minority neighborhoods. Because Tennessee's drug-free zones include day cares, libraries, and parks, it's almost impossible to escape them in some neighborhoods. And getting caught with drugs in a zone mean the difference between being eligible for probation and serving years of hard time.

If Bryant "had lived in a wealthy, residentially-zoned suburb like Belle Meade, then he likely would have been eligible for release after serving just two years and five months in prison for the exact same conduct," Bryant's petition states. "Because Mr. Bryant lived in the Edgehill Housing Projects, however, Mr. Bryant must serve a mandatory minimum sentence of at least 15 years before he even becomes eligible for parole."

Here's what the Edgehill neighborhood of Nashville that Bryant lived in looks like. The tan areas are those covered by drug-free zones:

That's why Nashville's current district attorney, Glenn Funk, doesn't pursue drug-free school zone sentences against defendants who haven't violated the core purpose of the law: putting children in danger.

Meanwhile, members of the Tennessee state legislature plan to advance a bill in the upcoming session to shrink the state's drug-free school zones from 1,000 feet to 500 feet. A similar effort failed in the state House last year.

But that's cold comfort for current inmates and their families.

"Calvin has been incarcerated since May 16, 2008 and it has affected our family in a major way," Bryant's sister LaShana writes in a letter attached to his petition. "Our father passed away 11 months after he was incarcerated, and our mother had developed several health issues. Calvin is not perfect, but he is a great man that has definitely grown and matured over the years. I pray that he is allowed a second chance to be released so that our family will be able to put this behind us and move forward."

You can read about all this and more in an investigation into drug-free school zone laws by myself and my colleague Lauren Krisai in the latest print edition of Reason. We obtained public records showing wide racial disparities in drug-free school zone sentences in Tennessee. We also got our hands on geographic information system (GIS) data showing that wide swaths of urban areas in the state are covered by these overlapping zones. In fact, 27 percent of Nashville, where Bryant was arrested, is covered in drug-free school zones.

If you're not a subscriber (see what you're missing?), keep an eye out to see the article on the Reason website in the near future.