What if anyone, not just Disney, could make cartoons featuring Mickey Mouse or Donald Duck? Or what if anyone, not just DC Comics, could publish comics featuring Superman or Batman?

A case argued last week before the U.S. Supreme Court could make those questions more than hypothetical.

Four years ago, Congress passed the Sonny Bono Copyright Term Extension Act, named for the late singer and congressman, who supported the entertainment industry's interests while a member of the House. Under the Constitution, Congress is empowered to "promote the progress of science and the useful arts, by securing for a limited time to authors and inventors the exclusive right to their respective writings and discoveries."

The key phrase here is, "for a limited time."

At first, creative works such as books enjoyed copyright protection for 14 years, with another 14 upon one-time renewal. After that, the works fell into the "public domain," meaning that anyone, not only the author or publisher, could reprint them without owing royalties.

Over the years, Congress has extended copyright numerous times. Just prior to 1998, copyright protection lasted through the life of the author plus 50 years, or, in the case of "corporate authors," 75 years.

For example, under the old law, a character like Superman, created 64 years ago, would fall into the public domain in 2013. After that, anyone would be free to use Superman — the 1938 version of him, anyway — with some restrictions.

Characters like Superman also fall under trademark law, which is another matter. For example, both DC Comics and Marvel Comics publish characters named Captain Marvel. But Marvel Comics holds the trademark to the name "Captain Marvel," so only Marvel can use the Captain Marvel name on the covers of its books.

But under the Bono Act, copyright holders get an additional 20 years of exclusivity.

Disney was a major backer of the Bono Act because without it Mickey Mouse would have entered the public domain in 2004. The Bono Act gives Disney exclusive ownership of the character until 2024. And you can bet that before 2024 rolls around, Disney and its lobbyists will be back in Congress seeking another extension.

Stanford University law professor Lawrence Lessig argued before the Supreme Court last week in Eldred vs. Ashcroft that the Bono Act violates the Constitution's "limited time" clause.

Lessig says the Constitution's framers recognized the public domain to be a vital part of the cultural landscape.

Ironically, the Disney empire is built on public domain works. "Snow White," "Cinderella" and "Beauty and the Beast" are not Disney creations, and Disney doesn't pay for their use.

Pre-1998 copyright law gave creators a lifetime to profit from their creations, plus an extra 50 years of exclusive use to pass along to their immediate descendants. Continued expansions of copyright protection benefit only corporations (not actual creators) while depriving the public of a rich cultural heritage.

Supporters of the Bono Act — movie studios, publishers and recording companies — claim the copyright extension is necessary to promote creativity. But then why do existing works need a retroactive extension? It's a fallacious argument, designed to hide the entertainment industry's real motives.

Hopefully, the Supreme Court will strike down the Bono Act. After all, how much poorer would we be today if Dracula and Santa Claus were not in the public sphere, where anyone can tell stories about them? How much poorer would Disney be without Snow White?