I like your idea. It is similar to a story I imagined about a "Superman" type alien on Earth, but what if he was really malevolent? What if there was a Zod type character, but no good equivalent to take him down? How would humanity deal with such a powerful, oppressing force, and what would the military put together to try and deal with him?
Well with fire power of course what else ,although they will learn from Superman and will learn some of his secret's and try and how is powers work and try to re create them.