United States government vs U.S. government

United States government and U.S. government both are nouns.

Word	Noun	Adjective	Verb	Adverb
United States government	Yes	No	No	No
U.S. government	Yes	No	No	No

As nouns, United States government and U.S. government are synonyms defined as:

United States government and U.S. government: the executive and legislative and judicial branches of the federal government of the United States

Other synonyms of United States government include U.S., United States, US Government.

United States government (noun)	U.S. government (noun)
the executive and legislative and judicial branches of the federal government of the United States	the executive and legislative and judicial branches of the federal government of the United States