It seems like every day we're hearing news of criminal defendants, some of them on death row awaiting execution, being exonerated by DNA evidence or otherwise having their convictions overturned. Often, they have spent decades in jail, all for crimes they did not commit. Beyond the moral and legal obligations to have a criminal justice system that doesn't incarcerate innocent people, there are financial reasons to make sure only guilty parties are convicted and go to jail.
A recent study found that serious mistakes in California's criminal justice system cost the state (and taxpayers) over $282 million between 1989 and 2012. This total included trials, incarceration expenses, appeals, and compensation for those wrongfully imprisoned in cases where the state failed to prosecute the right person or obtained flawed or unsustainable convictions. These are mistakes that must be avoided at all costs.