Put another way, the supposition on which our mass incarceration is premised—namely, that it materially reduces crime—is, at best, a hunch. Yet the price we pay for acting on this hunch is enormous. This is true in the literal sense: it costs more than $80 billion a year to run our jails and prisons. It is also true in the social sense: by locking up so many young men, most of them men of color, we contribute to the erosion of family and community life in ways that harm generations of children, while creating a future cadre of unemployable ex-cons many of whom have learned in prison how better to commit future crimes. And it is even true in the symbolic sense: by locking up, sooner or later, one out of every three African-American males, we send a message that our society has no better cure for racial disparities than brute force.