Sometime between 9 and 11 a.m. EST today, a Missouri man walked out of prison after serving 21 years of a life-without-parole sentence.

Jeff Mizanskey received that sentence in 1994. His crime? A non-violent illegal marijuana transaction, his third offense after two previous pot convictions.

Mizanskey’s two priors were for crimes involving more than 35 grams of cannabis—in 1984, he sold an ounce to an undercover agent; when his home was raided as a result, about half a pound was found there. His second arrest was for possession of less than three ounces, in 1991.

Then, in 1993, Mizanskey was arrested with a group and charged with possession and intent to distribute about 7 pounds of cannabis. Mizanskey went to trial, was convicted and, as a “prior and persistent offender,” was sentenced to life without the possibility of parole. (The principle actor in the case pled guilty and received a 10-year sentence.)

No doubt, Jeff Mizanskey knew the cannabis was illegal, and he is responsible for his actions. But his crimes were non-violent, and today these amounts fall well within the possession limits of many medical and adult-use cannabis states, including Maine’s.

According to a 2012 study by the VERA Institute of Justice, it then cost about $22,000 per year to incarcerate one inmate in a Missouri prison (“The Price of Prisons: What Incarceration Costs Taxpayers”). That means that the State of Missouri spent nearly half a million dollars over the last two decades to incarcerate one non-violent cannabis offender.

Mizanskey’s commutation required the dedication and tireless efforts of his family and legal team, plus the dedicated work of a group of Missouri-based advocates and supporters nationwide, who brought pressure on Missouri’s governor to review his case and commute it, allowing him parole. These resources may not be available to other citizens who are still serving life sentences for non-violent cannabis crimes at either the state or the federal level.

The effort to legalize cannabis for responsible adult use is not simply about allowing adults to choose a safer recreational substance. Legalization efforts must also work to undo the legacy of harsh sentencing for non-violent cannabis crimes at both the state and federal levels, thanks to policies enacted while our nation and individual states were in the grip of modern “Reefer Madness.”

Missouri’s “three strikes” law is set to expire on Jan. 1, 2017. And today, somewhere in the nation’s heartland, Jeff Mizanskey will get to hold and play with his grandchildren for the first time in more than twenty years.