Back that up with some actual Florida law or bit of jurisprudence, please.
Here you go, start digging.
What other evidence would the prosecution have for 2nd Degree? There is more to this than what the media have been portraying, and in the affidavit it purports that Zimmerman confronted Martin.
Now, if Martin felt threatened(stranger in a strange neighborhood), and attacked Zimmerman, Zimmerman cannot claim self-defense when he initiated the contact.
That is what this case will revolve around.