I would be surprised if anyone at Disney took the implicit threat in the letter from the Democratic leadership to be anything other than hollow. The fact is that nobody would dare threaten to take away Disney or ABC's broadcast rights. It's not going to happen. People would rise up in Disney's defense.
Instead, why not sponsor a bill to revoke the Mickey Mouse Protection Act (aka, Copyright Term Extension Act of 1998). Merely sponsoring such a bill should send the appropriate message to Disney. Actually passing such a bill after Democrats regain control would be even better. (For an explanation of why, go here:
http://writ.news.findlaw.com/...)
As an entertainment company, Disney creates value for its shareholders by leveraging the rights granted to it by the government in the form of copyrights. Therefore, although the first Mickey Mouse cartoon, Steamboat Willie, was published in 1928, Disney's lawyers will bring the might of the federal government crashing down on you if you paint Mickey on the walls of your nursery school.
Why would Disney threaten nursery schools? Because copyrights are the lifeblood of their business. Cartoon character themed shwag, amusement parks, videos, etc. allow Disney to take a relatively small investment (i.e., the cost of producing and promoting the new characters) and turn them into an extended profit stream. Or, if Disney had its way - an endless profit stream.
In short, copyrights are Disney's family jewels. If we mean business, then threaten to kick them.