Many mandatory minimum laws revolve around drug-related crimes - which is what is flooding our system.  An example would be someone being caught with as little as half a gram of any substance containing even trace amounts of fentanyl would send a person to federal prison for at least 5 years.  Thats 5 years in prison for having trace amounts of an illegal drug, vs. 4 years in prison for shooting an assault rifle into a business while it was open.