It is precisely in these terms that I wish to discuss a preeminent moral challenge for our time — that imprisonment on a massive scale has become one of the central aspects of our nation’s social policy toward the poor, powerfully impairing the lives of some of the most marginal of our fellow citizens, especially the poorly educated black and Hispanic men who reside in large numbers in our great urban centers.
Addenda: Glenn Loury isn't a libertarian. I assumed he was because what he wrote was basically consistent with libertarianism and it was published by a libertarian source. However, he's apparently on the left. He's had quite an interesting career, including a while as a neo-con. I recommend the article.
Original link thanks to Marginal Revolution.