Novus Robotics Inc (NRBT)

[willlbone]

Looking under “Born in the U.S.A.” (song) Wikipedia the phrase “United SOVIET of America” was in the first sentence in BOLD. It is gone now. (Perhaps a prank.)
I was looking for "USA" used as a noun which is rare.
Which is the more formal way to abbreviate the United States of America? Is it U.S. or U.S.A. or USA? You will find U.S. (disambiguation) used as an modifier, for example, U.S. navy, U.S. president, U.S. dollar, but seldom will you see USA used as a noun, for example, Miss USA. Punctuation has changed in the last 10 years. Thus 1900’s has become 1900s and Ph.D. has become PhD and PhD’s (plural) has become PhDs.

The New York Times style guide says recommend U.S. (periods but no space).
ACS scientific style guide allows US (no periods no space).
The Chicago Manual of Style says United States as a noun should be spelled out.