The only thing I can think of is that they didn't want to "defend" a murder two case. IOW, let the prosecution think it's trying a murder 1 case with self defense, then get in the evidence for a murder 2 charge so there's no evidence presented to refute it.
In at least one other case Juan has tried, murder 1 was charged and he couldn't prove it, so he requested a murder 2 charge and the defense objected. The court charged murder 2 anyway and the State got that conviction.
If the posts I'm reading are accurate, the State psych is testifying to BPD. Which doesn't support premeditation at all -- the opposite, in fact. Can't wait to see how it comes out. jmo
Arias' diagnosis is separate to proving premeditation under the laws of AZ.
As I understand premeditation, Arias must have
knowledge of a plan or Intent, and
reflection of that knowledge before killing of another.
Below is the actual definition of the Arizona jury instruction:
Pr-meditation means intent or knowledge to kill another human being.
"Premeditation" means that the defendant intended to kill another human being or knew [he] [she] would kill another human being, and after forming that intent or knowledge, reflected on the decision before killing. It is this reflection, regardless of the length of time in which it occurs, that distinguishes first-degree murder and second-degree murder. An act is not done with premeditation if it is the instant effect of a sudden quarrel or heat of passion. [The time needed for reflection is not necessarily prolonged, and the space of time between the intent or knowledge to kill and the act of killing may be very short.] pg PDF 71
"Intentionally" or "With Intent To" Defined: means that a defendant's objective is to cause that result or to engage in that conduct.
Intent - Inference
Intent may be inferred from all the facts and circumstances disclosed by the evidence. It need not be established exclusively by direct sensory proof. The existence of intent is one of the questions of fact for your determination.
"Knew" or "Knowingly" Defined: means that a defendant acts with awareness
of, or belief in, the existence of conduct or circumstances constituting an offense. It does not mean that a defendant must have known the conduct is forbidden by law.
REVISED ARIZONA JURY INSTRUCTIONS (CRIMINAL) Third Edition 2011
http://www.azbar.org/media/292098/2011_cumulative_supplement.pdf