Let's move the speculation and rumination to a new thread while I pass this off as an original thought:
From time to time I see lefty commenters offering a variation of "If we can only get Zimmerman inside a courtroom and on the stand, we will rip him apart. And he can't invoke the Stand Your Ground defense without taking the stand".
Keep hope alive. But setting aside his Fifth Amendment right against self-incrimination, Zimmerman can simply take the stand and explain that, although he cooperated with the police as best he could and made whatever statements he made to them, due to the blows on his head suffered during the scuffle as well as natural post-traumatic stress, his memory of the details of that night is hazy.
Which may leave us with a trial with *zero* witnesses to the outset of the fight between Zimmerman and Martin. And the defense seems to have witnesses who saw Zimmerman on the bottom getting pummeled during the scuffle. Zimmerman can't prove Martin started it, but he doesn't need to, and no one living can say he didn't.
Unless the police turn up some heretofore silent but credible witness, we may know about as much as we are going to know, which doesn't look anywhere close to proving that Zimmerman did not act in self defense.
UPDATE: CNN reports on Joe Oliver, a friend of Zimmerman's:
[Zimmerman is] being treated for post-traumatic stress disorder, for depression, for insomnia," Oliver said.
OK. PTSD it is.