I think there are a lot of people in prison who do not belong there. But there are also a lot of people in prison who really, really belong there, to keep them away from the rest of us. Of course, that is pretty much non-controversial because I have said anything particularly useful, say, which prisoners fall into which category. You would no doubt think it pretty lame if I declared that the guy who committed eight ax murders should be there, but not the guy with four unpaid parking tickets. You would be right, of course, but that would put me way ahead of Marie Gottschalk, a political scientist at Penn, who bravely takes to the pages of the Washington Post to come out in favor of less incarceration.

Many of today's crime control policies fundamentally impede the economic, political and social advancement of the most disadvantaged blacks and members of other minority groups. Prison leaves them less likely to find gainful employment, vote, participate in other civic activities and maintain ties with their families and communities.

[Obama] generally has not focused on the perils of mass incarceration. Neither has Sen. Hillary Clinton, though the $4 billion anti-crime package she unveiled last week did call for elimination of the federal mandatory five-year sentence for minor crack cocaine violations.