Some ideas on how it could work:
- Read through the connection data (phone,email etc) from key figures of the Bitcoin community to gain insider knowledge
- Infiltrate core development and replace Bitcoin key figures with NSA staff
- Discredit respected members of the community
- Kill people, if they don't corporate.
I think they would start by buying a bitcointalk member account (at least hero level) and making a post asking for ideas... something like "How could NSA take control over Bitcoin?"

Blast! My evil plan is foiled.