What happened to Obama's Army of 2008?
Instapundit has a great answer.
The story tells the tale.
Not even sorcery may be able to rekindle the excitement many first-time voters showed back then. "The popularity of the President with these voters is not a transferable asset," says Jamal Simmons, a Democratic strategist. "I don't think it's realistic that they would ever be able to replicate the unbridled enthusiasm. It's like a first kiss: you can never experience it twice."