Writer's Fallout Shelter

Alright, let's see if we can get this thread going again.

I'm about to hit graduate school for creative writing. Trying to see if they'll let me work on a high fantasy story that has incredible depth and breadth in real life issues (socially reflective, possible political endeavors by the characters, the existential question of man's interaction with and existance in nature, the nature of love, the nature of death, etc). However, the story requires that I do a staggering amount of research.

Another case of the story dictating what the author should do.

My question for everyone here is this: When researching for a story, do you research just as far as it takes to write your scenes? Or, do you research far enough that you become an expert on the topic, even if you don't use half of what you learned?

I guess it's another case of authors presenting their stories in a manner that shows they know what they're talking about, and one where they only make it appear as if they do.