Quote Originally Posted by Philippus Flavius Homovallumus View Post
Cornwall was part of Wessex before England existed, then Wessex became England, then England was united with Wales, then Scotland was united with those two, then Ireland was united with Great Britain.

Cornwall is, therefore, not a constituent part of the "United Kingdom" and to describe it as such is a classification error.
Doesn't address my question. I would say that while Cornwall is not a constituent of the Treaty of Union, it is a constituent of one of the constituents of the Treaty of Union, and so as a subset of that constituent is indeed "a part of" (or similar designation) the UK. Just as both the city of New York and the State of New York are part of the United States, even though New York City is neither a founding member nor a state member at all.