When the Bureau of Prisons instructed prisons to remove all works from nine publishers that were on a list of dangerous religious reading materials, the ban raised relatively little fuss. Although the right of prisoners to practice their faith has Constitutional backing as well as legislative reinforcement through the Religious Land Use and Institutionalized Persons Act of 2000, that right tends to be manifested through behaviors such as diet, prayer and personal appearance (e.g. Jews' keeping kosher, Muslims' worshipping five times a day or Sikhs' wearing a turban). Even practices related to dangerous, violent and racist belief systems* receive some protection, as with the Five Percent Nation, a nontheistic offshoot of the black supremacist Nation of Islam. However, the right with regard to religious literature is a negative one; a right to receive, rather than a right to have the prison provide such information. A Five Percenter must be allowed to read whatever ridiculous pamphlets he has brought to prison, but the prison has no affirmative obligation to furnish them to him.
Therefore I am inclined to think that the Bush Administration's decision to have the Bureau ban all reading material from prison libraries that does not appear on a short list of what is permitted falls into the category of "stupid, possibly financially biased, but not unconstitutional." (Cf. the awarding of military contracts.) If the Bureau of Prisons wanted to burn every book in the prison libraries, or just the ones with red covers, it could do so without infringing the First Amendment, so long as it didn't single out a particular religion for such persecution. Nonetheless, it is the sort of policy that makes for good Daily Show material: an idiotic overreaction to legitimate concerns about prisons as a breeding ground for conversion to violent religious ideologies. I can see why the government would perceive particular material as dangerous and thus appropriate for excising, but assuming that Reinhold Niebuhr must promote dangerous beliefs because he didn't make a C.S Lewis-heavy list of Approved Christian Theology (and given Lewis's views on the need for women to obey their husbands, I don't see him as a pure beacon of enlightened thought) is grotesquely bad thinking. If the chaplains at individual prisons are so bad at vetting what comes into their libraries that the system needs to be managed from Washington, perhaps the Bureau should look at where it gets the chaplains instead.
* The Southern Poverty Law Center is a wonderful resource, but I concur with Tim Wise that the name doesn't seem apropos:
To that effect, we have groups like the Southern Poverty Law Center spending all their time taking a handful of Nazis to court, tracking hate groups on the Internet, and sending out stamps that say "teach tolerance" to folks on their mailing list so as to raise more money (despite an endowment in the tens of millions of dollars) -- all so they can do anything but help poor people -- which, given their name, I had always assumed was the point. In addition to the Center, there are at least a half-dozen organizations nationwide that focus almost exclusively on doing battle with "the far-right." They can tell you everything you’d ever want to know about even the most insignificant Christian Identity church (members of which believe Jews are Satanic and persons of color are "mud people" without souls), or let you know who attended the most recent meeting at the Aryan Nations compound, all of which might be helpful the next time you’re sitting around playing militia trivia with Morris Dees, but is likely of little use the rest of the year.