My question is about whether proper nouns (used as the subject of a sentence) should be considered as singular or plural. The proper nouns "The United States" and "The Duck Variations" are the name of a country founded in 1776 and the name of a play written by David Mamet in 1972. I believe it is correct to write "The United States was founded in 1776", because "The United States" is a proper noun used as a singular phrase, even though it is a collection of states. Similarly "The Duck Variations" is a play for the theatre, written as a single work consisting of 14 short acts which are always performed together.
My question is, do I write "The Duck Variations was written in 1972" or "The Duck Variations were written in 1972"? The plural form seems correct, but I cannot find any rule saying which should be used. Also if the plural is correct, what rule distinguishes the usage of the proper nouns "The United States" and "The Duck Variations"?
I have already looked at:
Can the name of a country be considered a plural noun, as a collective of e.g. its citizens? which leads on to Are collective nouns always plural, or are certain ones singular?
Pluralization of proper nouns: regular or irregular?
Collective nouns with plural verbs: the 'American practice/s' versus the 'British practice/s'
This final article seems the most relevant, although it does not answer my question:
"Are" vs. "is" for proper nouns which sound plural (such as band names)
