Mickey Mouse curve finally is defeated. Now it should be beaten back down which is harder.
This would seem to indicate that the parent was right -- the long extension to copyright is because the US decided to match Europe's protections. Although, on second reading of your comment, I wonder if you mean that US companies convinced Europe to provide longer protections, with the intent to then make the US match the policies they pushed in Europe? That seems very elaborate
Example: https://www.eff.org/deeplinks/2013/03/ustr-secret-copyright-...
> The Senate Report gave the official reasons for passing copyright extension laws [...] to ensure adequate copyright protection for American works in foreign nations
... it also notes:
> The report also included minority opinions by Herb Kohl and Hank Brown, who believed that the term extensions were a financial windfall to current owners of copyrighted material at the expense of the public's use of the material.
And who supported the bill and lobbied for it?
> Since 1990, The Walt Disney Company had lobbied for copyright extension. The legislation delayed the entry into the public domain of the earliest Mickey Mouse cartoons, leading detractors to the nickname "The Mickey Mouse Protection Act".
> In addition to Disney, California congresswoman Mary Bono (Sonny Bono's widow and Congressional successor), and the estate of composer George Gershwin supported the act. Mary Bono, speaking on the floor of the United States House of Representatives, said: "Actually, Sonny wanted the term of copyright protection to last forever. I am informed by staff that such a change would violate the Constitution. ... As you know, there is also [then-MPAA president] Jack Valenti's proposal for term to last forever less one day. Perhaps the Committee may look at that next Congress."
> Other parties that lobbied in favor of the Bono Act were Time Warner, Universal, Viacom, the major professional sports leagues (NFL, NBA, NHL, MLB), and the family of slain singer Selena Quintanilla-Pérez.
So, primarily American corporations and individuals looking for a "financial windfall", including Sonny Bono himself who would have liked the act to completely violate the US constitution and make copyright last forever.
What you don't see on this list are any European organisations asking the USA to match their own copyright durations.
People with copyrights today, don't lose anything. Only new ones have shorter terms.
Reducing the length of existing copyright terms might be considered an ex post facto law. Those are explicitly prohibited by the Constitution.
The Constitution states that copyrights must be limited in length. Retroactively extending the duration of existing copyrights (as opposed to new copyrights) should be unconstitutional, but the Supreme Court said in Eldred v. Ashcroft that it’s fine—wrongly, in my opinion. Correcting them would require an amendment.
It's arguable that "about a century" was not what the drafters of the Constitution had in mind when writing "a limited time", but convincing the Supreme Court of that would be harder than an actual amendment.
But isn't the ex post facto prohibition mainly related to consequences of past actions rather than general public policy? No one is going to jail because copyright terms were reduced to 15 years from 95.
I think such a reduction would definitely be constitutional if it were phrased as "all new copyright terms will be XYZ, and existing ones will expire XYZ from the effective date of this act," but I'm not totally convinced that's necessary.
Takes longer than changing the terms of existing grants, but so what.
No, that is definitely not an ex post facto law. That's not even close to what the ex post facto law clause covers (dealing with punishments for actions that were kosher at the time they took place).
There is an argument that shortening copyrights is prohibited by the takings clause. But I think there is a very good argument that shortening them isn't prohibited by the takings clause (for the same public-private interest balance reason that led to the first amendment arguments in Eldred v. Ashcroft and Golan v. Holder failing).
The USA might get away with it, but smaller countries likely can't.