The US Treasury's Office of Foreign Assets Control, one of the various US agencies involved in policing sanctions, terrorist finance and dirty money, is being sued by the US committee of PEN and a variety of academic organisations over regulations that (they claim) prevent books originating in countries the US maintains sanctions on being published in the States. Here is the writ, with details on exactly what they are arguing about. Amongst other things, they point out that the regulations effectively mean that other countries' censorship is in a sense extended to the US, because only works that have already been published there may be republished.
The same organisation took until the 22nd July this year to add Viktor Bout to its blacklist, and even then didn't think to include any of his companies or aircraft. So unless he showed up in person, it wasn't much use. In fact, it was only this year that they got around to adding the Taliban as an organisation to the list.
But they did manage to pass regulations on which books you can read.