I don't profess to know what's wrong with our criminal justice system but our system must be broken.
wikipedia shows: The incarceration rate in the United States of America is the highest in the world today. As of 2009, the incarceration rate was 743 per 100,000 of national population (0.743%). In comparison, Russia had the second highest, at 577 per 100,000, Canada was 123rd in the world at 117 per 100,000, and China had 120 per 100,000.
While Americans represent about 5 percent of the world's population, nearly one-quarter of the entire world's inmates have been incarcerated in the United States in recent years. Imprisonment of America's 2.3 million prisoners, costing $24,000 per inmate per year, and $5.1 billion in new prison construction, consumes $60.3 billion in budget expenditures.
Throwing the book at defendants must be happening a lot in the US... and it doesn't seem to be doing much good. Sigh!