Yesterday, Mr. Page said, "...music whose copyright [in Britain] 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."

This would not be possible in America, due to the 'ex-post-facto law'
prohibition in our constitution.  That is, one can not make illegal
something that was legal to do, if done before the law is passed.

Prior to January 1, 1978, American copyright duration was 28 years,
routinely renewable to 56 years.  On that date, copyright durations
were extended to 70 years, to conform with the longer terms common in
other countries.

The 'Sonny Bono Copyright Term Extension Act of October 27, 1998'
further extended the terms of copyrights, to as much as 120 years.
Read: http://www.copyright.gov/title17/92chap3.html for the complex
rules governing copyright term lengths.

However, at the time of the act in 1976, works published before 1923
were already in the public domain, being more than 56 years old.  These
works were _not_ put back under copyright, since anyone who might have
used them freely as public domain works would be protected from
liability by the 'ex-post-facto' provision.  But any copyrights then
still in effect (less than 56 years old) were extended.

Thus we have a sort of 'sliding scale' in America; any music published
before 1923 is in the public domain.  Any music published in 1923 or
later, is protected.  This cutoff date will probably not advance beyond
1923 until about 2043!

Ethical web suppliers of on-line music, such as http://parlorsongs.com/
respect this rule, and do not distribute MIDIs, MP3s, or RAMs of music
published after 1922, unless the appropriate fees are paid.

Richard Vance