Federal Judge Richard Kopf at Hercules and the Umpire has this post with a funny cartoon and a serious point.  Down in the comments, he concedes that the point is poorly worded in the original post and substitutes this wording:

My point is really two fold: (1) most of the folks I see should go to prison and most reasonable observers would agree; (2) in the few "close" cases where a judge must decide between prison and probation, I am not good at making that decision personally and [18 U.S.C.] section 3553(a) is not much help.