[1] https://en.m.wikipedia.org/wiki/Demonyms_for_the_United_Stat...
A person from the US has been elected as the Pope, you have to come up with a title for this news piece.
You have these two options:
A) First American Pope elected ...
B) First US Pope elected ...
A is ambiguous because "American" means a country for 4% of the world and a continent for 96% of the world. Also, the pope that just died happened to be from Argentina, and also happened to be the "First American Pope" for 96% of the world, adding to the ambiguity.
B does not have any issues and is correct from whichever angle you want to approach it.
Which one do you choose?
Ask foreign speakers if you don't believe it.