I think the state may concede Trayvon Martin punched Zimmerman before Zimmerman shot him. Its theory seems to be that Zimmerman was the aggressor and the slug wasn't hard enough for Zimmerman to reasonably fear serious bodily injury or for his life and that he had an opportunity to avoid the use of force.

The state's affidavit carefully and intentionally avoids saying who threw the first punch. It makes no claim Trayvon did not turn their final encounter from one of words into something physical.

The argument that Zimmerman was the aggressor is unlikely, in my view, to prevail. Here is the aggressor statute. Since Zimmerman isn't charged with an independent forcible felony aside from the shooting, only the second section could apply:

76.041 Use of force by aggressor.—The justification described in the preceding sections of this chapter is not available to a person who: (2) Initially provokes the use of force against himself or herself, unless : (a) Such force is so great that the person reasonably believes that he or she is in imminent danger of death or great bodily harm and that he or she has exhausted every reasonable means to escape such danger other than the use of force which is likely to cause death or great bodily harm to the assailant; or ( b) In good faith, the person withdraws from physical contact with the assailant and indicates clearly to the assailant that he or she desires to withdraw and terminate the use of force, but the assailant continues or resumes the use of force.

The problem for the state is that profiling, following and even pursuing Trayvon is not sufficient to make Zimmerman the aggressor under the statute. To be an aggressor, Zimmerman had to provoke the force used by Martin. Provoking a state of fear is not enough. Also, Zimmerman's provocation has to be contemporaneous with Martin's use of force against him. It can't be the result of something that happened earlier.

See, for example, Johnson v. State, 65 So. 3d 1147, 1149-1150 (Fla. Dist. Ct. App. 3d Dist. 2011), which is consistent with the Florida Jury Instructions.

Specifically, section 776.041 "[s]ubsection (2) precludes the initial aggressor from asserting self-defense where he or she is the individual who provoked the use of force contemporaneously to the actions of the victim to which the defendant claims self-defense. .... we note that the initial provocation would necessarily had to have been contemporaneous to the actions of the victim, as described in subsection 2(a), which the defendant claims self-defense.

Initiating the encounter is not enough to make one an aggressor. To be an aggressor, one must provoke the use of force. Profiling, following and pursuing someone is not provocation for a punch in the nose or banging someone's head into concrete, as Zimmerman says happened, an account which may be consistent with the signs of bandages witnessed by his neighbors. (His account may also be backed up by his medical records or photos taken by police that night, we don't know that yet.)

If I follow you down the street and you don't know why, you run away, and then I finally catch up with you, you aren't allowed to respond by punching me. My following you is not an action that warrants or can be deemed to provoke such a violent response from you.

If Zimmerman is not the aggressor, if he didn't provoke Martin's punch, he had no duty to retreat, and so long as his fear of serious bodily injury or death from Trayvon's punch and/or beating his head into the ground was reasonable, he's not guilty.

Even if he was the aggressor, which triggers a duty to retreat, if retreat isn't possible, and he fears serious bodily injury or death from the victim's attack, he can use deadly force. How could he retreat, if he was on the ground locked in a struggle or being punched?

If the case gets to a jury, the state will have to prove beyond a reasonable doubt to all 12 jurors, that Zimmerman did not reasonably fear serious bodily injury or death from Trayvon's acts.

There were no witnesses who came forward that night and said they saw the beginning of the struggle or that Zimmerman was the aggressor.

Since not a single witness can say who started the fight or that Trayvon didn't first punch Zimmerman, not a single witness can refute Zimmerman's version beyond a reasonable doubt. The state will need credible forensic evidence or proof that Zimmerman significantly contradicted himself in interviews or provided a version that of events that is not possible.

Trayvon's phone friend said she heard Trayvon say Zimmerman was following him, that Trayvon got away from him, and then he found Trayvon again. She says she heard Trayvon ask Zimmerman why he was following him, Zimmerman responded with "What are you doing here?" and then the line went dead. She has no idea who struck first.

I don't see how, even putting aside the credibility and hearsay issues raised by her statement, she helps the state on the issue of provocation. Following someone without just cause and asking them to justify their presence when they had no right to do so, is not sufficient provocation to warrant a punch in the nose.

So if Zimmerman didn't provoke the punch in the nose, he isn't the aggressor, under the law. To repeat:

776.041 Use of force by aggressor.—The justification described in the preceding sections of this chapter is not available to a person who: (2) Initially provokes the use of force against himself or herself, unless: (a) Such force is so great that the person reasonably believes that he or she is in imminent danger of death or great bodily harm and that he or she has exhausted every reasonable means to escape such danger other than the use of force which is likely to cause death or great bodily harm to the assailant; or...

Even if I''m wrong, and Zimmerman's acts are somehow deemed to be provocation, they still had to be contemporaneous with the punch. And, more importantly, even as an aggressor, Zimmerman would still be justified in shooting Travon under Florida law if he feared he was in imminent danger of death or great bodily harm and if he couldn't extricate himself from Trayvon's punches and banging his head into the ground.

If Zimmerman has evidence of injuries, from his own account, neighbors' accounts and especially medical records, what else can the state argue to preclude self-defense? That Trayvon just gave him a little shove, Zimmerman slipped and fell, breaking his own nose, and then slipped and fell again on his back, banging his head on the concrete?

Here's a comparison of Zimmerman's profile from an undated photo before the shooting and when he was booked into the jail. I see a smooth bridge in the former and a bump in the latter, but maybe that's just me.

This may all come out at the bail hearing where the state's burden is to show "the proof of guilt is evident and the presumption great," which in Florida, means a higher burden than proof beyond a reasonable doubt. See the order in the Wyche case. Given this burden, I won't be surprised if the State agrees to bail to avoid the hearing, so that the first time it has to disclose its proof in court is at the Stand Your Ground hearing.