“Congress wrote mandatory minimum laws in the 1980s to send a clear message to drug dealers: if you are caught with a certain amount of drugs, no matter the circumstances, you will go to prison for a long time. Two ounces of methamphetamine, for example, means ten years in prison. If it’s your third such crime, that’s life in prison. Normally, choosing a fair sentence is the judge’s job, and no reasonable judge would send 17-year-old Katie to prison for 20 years for agreeing to sell a quarter-gram of her personal heroin supply to a friend. But since selling heroin that causes ‘death or serious injury’ is a specific mandatory minimum offense, if the prosecutor charges Katie with the offense and she is found guilty, the judge must sentence her to 20 years.^“