Opinion: What is the purpose of incarcerating people with serious mental illness?

During a recent conversation with a friend, she remarked on a man in the news. He was thought to have a mental illness and was recently released from prison, then soon after was rearrested for a similar crime. She concluded therefore that he should have never been let out. Truth be told, a few years ago, I may have thought the same thing. Now, I’ve unfortunately found myself with a front row seat to what it really means to be incarcerated. So instead, we had a deeper conversation.