The culture that was Chicago

More than three-quarters of turn-of-the-century Chicago homicides led to no criminal punishment — not because the perpetrator could not be identified, but because no jury would convict.  One historian’s study of Chicago homicide cases in that period reads like a compendium of bar fights that got out of hand, nearly all of which took place in front of witnesses and most of which ended in defense victories.  A system in which easily identified perpetrators succeed so readily is bound to have a small prison population.

That is from the new and excellent book The Collapse of American Criminal Justice, by William J. Stuntz, recommended to me by the excellent Chug Roberts.