For the same reason that the right to bear arms should not be abridged, regardless of what a 'militia' actually is. Well, now we're getting into semantics. The 2nd Amendment says that because of X, the right Y shall not be infringed. X is the motivation for Y but doesn't limit it. The copyright clause says that Congress has the power to do X (promote arts and sciences) by doing Y (granting copyrights and patents). I would argue this means that Congress can do Y *only* if it is related to achieving the goal of X.
As long as Congress makes a determination, however stupid or corrupt, that lengthening the span of copyrights aids progress, the Courts, IMHO, should not be second guessing them.
For lengthening copyrights on future works, I'm forced to agree. But I don't on the retroactive extension, because there is no conceivable way in which that aids progress.
But this is all moot, as 77% of SCOTUS disagrees with me. Like you, I intend to give this law every bit of respect that it deserves.
"
promote arts and sciences"
The useful arts -- meaning technical and engineering. The Founders did NOT include the "arts" as we use that term today, meaning "fine" arts, or fictional writings, or even journalism.
"To promote" parallels the form "To promote the general Welfare" in the Preamble, from which it may be inferred that "promoting the useful arts and sciences" is a method of promoting the general welfare. That is, what is to the common benefot of all and favors none prejudicially. Promoting useful ideas and knowledge is part of the general welfare.
It is hard to make that case for a cartoon, a song, a piece of music. Oh, they give pleasure, relief and serenity at times, but that is not at the level of knowing how to solder one piece of tin to another, nor how to properly care for cattle, nor to the level of clear constant value in a good map.
The public constraints of copyright to literature and music have grown from almost nothing to the major pratical portion of copyright. The push for yet more contraints on the public by grants of copyright began late in the 19th century and has continued unabated, if not strengthed. Here is a part of a timeline from a British site:
- 1884 - The Society of Authors is founded for "the maintenance, definition, and defence of Literary Property". The Society's first objective is to obtain copyright protection for English authors in the United States. Among its other aims, it also lobbies for a Bill for the Registration of Titles.
- 1886/7 - The seminal Berne Convention for the Protection of Literary and Artistic Works is signed (in Berne, Switzerland). It intends to give international copyright protection to the creative works of the citizens of European member state signatories. Works protected include: novels, short stories, poems and plays; songs, operas, musicals, sonatas and symphonies; drawings, paintings, sculptures and architectural works. In the International Copyright Act of 1886, Great Britain gives assent to the obligations of the Berne Convention. This Act abolishes the requirement to register foreign works, and introduces an exclusive right to import or produce translations. The U.K. ratifies the Berne Convention with effect from 5th December, 1887. The U.S., however, remains governed by its 1790 Copyright Act, and is not subject to the Berne Convention. Longstanding U.S. literary and musical piracy of works by European authors and composers (and vice-versa) continues to be an accepted way of life for publishers, until finally brought to an end by the establishment of separate bilateral copyright agreements with the U.S.. The Berne Convention is revised in 1908 and 1928. The Berlin Act of 1908 extends the duration of copyright to the life of the author plus 50 years, takes account of new technologies, and declares that formal registration is unnecessary in order to hold a copyright. The Rome Act of 1928 is the first to codify the moral rights of authors and artists.
- 1909 - A major third revision to the U.S. Copyright Act is completed. More categories of protected works are included than ever before (effectively, all works of authorship). The renewal term is also extended from 14 years to 28, taking the total possible period of protection to 56 years. With respect to music, Congress declares: "The main object to be desired in expanding copyright protection afforded to music has been to give the composer an adequate return for the value of his composition …"