[jcranmer]

The copyright to Hitler's Mein Kampf passed to the Bavarian government, which after WW2, refused to allow it to be printed until the book fell into public domain.

Browsing the list of in rem cases in the US turns up quite a few cases where the US actually seized several pornographic books such as Lady Chatterley's Lover, which is perhaps a little more in line with what you were thinking about.

[cafard]

I was once on a tour of St. Albans, a very expensive private school in Washington, and Mein Kampf was the first book I noticed on the shelves. I have to suppose that the school has confidence that any boys who read it will not be indoctrinated.