Amazon (UK and Germany) are currently saying this can't be dispatched to the US. FYI.

Is there any rhyme or reason to which items can be dispatched to the US from amazon.co.uk and which can't? Is it related to how new this one is? I've ordered several Harper Collins Tolkien books via amazon.co.uk and they've all shipped rather smoothly to the US, but they've also all been older books.