Question

What is the legal protection afforded an expression of an idea, such as a song, book, or video game?

Answer 1

First, apply for a copyright or a patent (depending on which of the above you are talking about).  However, that takes time.  You can consult an intellectual property lawyer.  If you can't afford one, you can use one of the free legal advice websites that will let you "chat" with a lawyer or law student in a specific area of law at no charge.