A couple of years ago, a woman I'll call Ann saw me give a television interview about prison sentencing reform. She phoned me right away to tell me about her son, who, she said, received a 10-year sentence in federal prison for his second marijuana possession. A lawyer was filing an appeal, but she didn't know if he would be successful.
Alas, I didn't have any hope to hold out to her. Congress seems even less likely than the Missouri legislature to shorten drug possession sentences, and such reform benefits are almost never retroactive, though there's no reason they couldn't be.