To those who think Casey has multiple personality disorder and is "The Nanny":
I don't know HOW they (the defense) would ever be able to pull this off at trial, seriously. People with real MPD usually have memory lapses from one personality to the next. The "main personality" (speculation: Casey Anthony) would not be able to turn on/off the "Nanny" at will, and would not know everything the Nanny personality did and said, at least until after all the personalities are merged together. People with MPD have certain traits none of which I see exhibited in Casey's behavior. They have real lapses in time and memory, can take on a different "appearance", speak in a different tone of voice, have a different handwriting, and different mannerisms.
Plus, she has ZERO history of MPD (that we know of), was seen by two psychiatrists before she was released on Padilla's bond (and passed the tests), and seems to deal with her stress by asking for meds (ala upon hearing of Caylee's remains being found). I would think if she had MPD, just one thing she would have done was switch into another personality upon hearing of Caylee's remains and not asking to be medicated (just one example).
I said once before that this case could only get crazier if she got on the stand and said, "I AM THE NANNY!" Could Baez attempt to go this route? Sure...but it would be more for the jurors, the press, the pundits and Joe Public to laugh about (ending on a preposition and I don't care).
Honestly, if Baez got Casey and a priest to say she was POSSESSED that would fly easier than a MPD defense.