I'll give some background info on coming up with this category -
I basically had two choices on region guidelines - either that a book be mostly set in that region, or the author be from that region. I chose the latter to prevent a region's nominations being filled up with foreigners writing fiction about a region, especially that every region may then have many U.S./U.K. author nominations since those countries have such huge and well-known literary traditions. That would defeat the purpose of sampling a region's literature, so I felt the more authentic approach was defining it by where the author comes from.
After that, I could've said an author should be from the region and
the book should be set in that region, but I didn't want to automatically eliminate so many books from fitting in any region, since many are set in places that the author is not from, and aside from other countries, there are even locations such as books set on the ocean, unknown or unnamed locations or science-fiction books set not on the earth, etc.
That said, I still knew there would be some books that would be sticky to categorise and still may not fit in any region, and this could include some ancient authors whose ancient regions were different from current ones (which, for example, is one reason I put Turkey in the same region as Greece instead of its current more closely culturally aligned neighbours in the Middle East) and authors who moved, especially ones who became citizens of another country. I figured this probably wouldn't be much of a problem but that we'd just take any questions on a case by case basis.
I was deliberate in my guideline wording. I purposely left out "originally" before "from" to leave a little wiggle room for authors such as Kazuo Ishiguro who moved at a young age. But in general, my intent in the wording was an author who grew up in and therefore was culturally aligned with a region, despite where they may be while writing a book.
Ironically enough, I specifically thought of Nabokov and Lolita while writing the guidelines for the category as a sort most extreme example I could think of that could challenge the guidelines (and since he was mentioned, I'll note that I also thought of Conrad too). My conclusion was that some few books just may not fit any region really under the spirit of the guidelines and would be better nominated in some other month. Having thought of Lolita while writing the guidelines, I’m really amazed it's now come up not only as a possible nomination but one that people want to push through to a win before the nominations even start and are using it to choose a region.
Reading some of your posts now, I feel ambivalent on the issue. Though I feel that perhaps technically Nabokov could be considered "from" the U.S. after a certain point, I still think that Lolita as a nomination for the U.S. wouldn't really fit the spirit of the category, and, as Hamlet53 pointed out, a concern is also where things might lead once the criteria is made so squishy, as he put it.
Also, I'm not particularly enthused about a particular region winning in a landslide based on the prospect of nominating one particular book, even if that book definitely fit that region. It just feels a bit like trying to choose your chick before the hen's even laid the eggs.
All that said, I'm happy with Canada & the U.S. (presumably) winning and am looking forward to whatever the nominations may bring once the poll's over.
And to be clear, as issybird mentioned above, it’s up to the group to decide on this one through nominations and voting.