Lee Carroll Brooker, a 75-year-old disabled veteran suffering from chronic pain, was arrested in July 2011 for growing three dozen marijuana plants for his own medicinal use behind his son’s house in Dothan, Ala., where he lived. For this crime, Mr. Brooker was given a life sentence with no possibility of release.

Alabama law mandates that anyone with certain prior felony convictions be sentenced to life without parole for possessing more than 1 kilogram, or 2.2 pounds, of marijuana, regardless of intent to sell. Mr. Brooker had been convicted of armed robberies in Florida two decades earlier, for which he served 10 years. The marijuana plants collected at his son’s house — including unusable parts like vines and stalks — weighed 2.8 pounds.

At his sentencing, the trial judge told Mr. Brooker that if he “could sentence you to a term that is less than life without parole, I would.” Last year, Roy Moore, chief justice of the Alabama Supreme Court, called Mr. Brooker’s sentence “excessive and unjustified,” and said it revealed “grave flaws” in the state’s sentencing laws, but the court still upheld the punishment.