Vox did an excellent background piece to go with Oliver's segment:
Oliver cited the story of several prisoners serving decades-long or life sentences for mandatory minimums — including Weldon Angelos, a father and nonviolent drug offender who's serving 55 years in prison for marijuana trafficking.
In 2002, police caught Angelos selling marijuana while allegedly possessing a firearm in three separate stings. Federal prosecutors stacked each of these stings into three offenses, with all the charges adding up to a 55-year minimum prison sentence with no chance of parole. Once Angelos was found guilty, the judge had to hand down this minimum sentence, regardless of his views.
Angelos's case is so egregious that the judge who handed down the sentence is now speaking out against it. "I do think about Angelos," Paul Cassell, the retired Utah judge who tried Angelos's case, told ABC News. "I sometimes drive on the interstate by the prison where he's held, and I think, 'That wasn't the right thing to do, and the system forced me to do it.'"
Oliver put the case in a different context. "He won't get out until he's 79," he said, "for selling something that's currently legal for recreational use in four states, and whose main side effect is making episodes of Frasier slightly funnier."