Wearing a Black Hat in the Movies
In fiction, it's true. Your hero, or protagonist, is limited by the antagonist. The antagonist can be nature in a "man against nature" story or some other problem that is equally mindless... maybe sickness or a virus. But most often the antagonist is a person or an organization of people... the bigger the better because the whole of the thing, of the movie, is going to be limited by the scope of the antagonist.
Which is why I don't mind much (if at all) when a foreign movie has the United States or some portion of it, in the role of antagonist. Without invoking an alien invasion, where can a story-teller find a more imposing force to pit against the heroes?