Not everyone can treat patients legally, and not everyone can hold a person’s life and future in their hands. That’s why we have medical schools and licensure fees and exams and state medical boards-to keep quacks and charlatans from hanging out a shingle. In America, though, we permit just about anyone to accumulate lethal weapons–like the AR-15 assault rifle responsible for so many mass shootings–with the power to end many people’s lives.