Mark Kinsler pointed us in the direction of a comprehensive article on
music copyright in the USA.  I scanned this in the hope of discovering
if the USA goalposts have been moved as they have here in the UK.
This refers to the time limit for copyright on music -- or anything
else, for that matter.

Our UK rules state that music is subject to a copyright licence if the
composer is alive, or has been dead for less than 70 years.  (This has
fairly recently been increased from 50 years.)  In the article I found
no mention of this time limit.  Does it exist in the same way in the
USA, and has it been similarly increased from 50 to 70 years?

Incidentally, music whose copyright had already expired under the
50-year rule, came back into copyright when the time limit was increased
to 70 years.  This is a classic case of "moving the goal posts" if ever
I saw one.

Regards,
John Page