"Let's buy a bottle of American white wine to give to her!"
Exactly. White wine is often translated as 'white grape spirit' to avoid exactly this confusion.
If you specify 美国白酒, are we now talking about white wine or is it understood as an American version of baijiu?
Because of the translation "white wine", 美国 is included to specify the type of wine. With 美国, you are then talking about the white wine originated from America.
Otherwise, without 美国, you are then generalizing 白酒 to some wines with different origins. Since 白酒 is first originated in mainland China before other countries, like Japan and Korea, either a place of origin or a wine type should be included (which can depend on the context).
That's not really what I was asking. What we think of as white wine is not at all even similar to what Chinese call 白酒 (白酒 is made from sorghum or other grains as opposed to wine which is made from grapes). That being understood, it would be possible for Americans (or any other country) to make 白酒 from grains in the same way that the Chinese do. My question therefore is - when you say 美国白酒, is that definitely white wine (alcohol made from grapes and originating from the US), or could it be 白酒 (the alcohol made from sorghum, but made in the US)?
The issue is the confusion between type of wine / liquor and nationality of wine / liquor. 美国 means American, nothing else. 白酒 means white (or clear) alcoholic beverage, nothing else. In a modern world, where (for example) "Scotch"whisky from Tasmania, Australia is winning world tasting competitions, you need to be precise to avoid mis-understandings.