There is some debate about whether or not the state in fact turned over this evidence. As I understand it, the state turned over an image of Treyvon Martin's cell phone in a format that the defense experts were unable to read. According to the state, this fulfilled their discovery obligations in this matter.

The basis of my reservation, which may seem extremely pedantic, is twofold:-

First, it's undisputed that Zimmerman spent several minutes following Martin while commenting on his suspicions to the police dispatcher. At some point Zimmerman exited his car, came face-to-face with Martin, and then they had an altercation. It seems quite plausible to me that Martin might have punched Zimmerman in the nose as alleged.

But it's not the case that Zimmerman was doing his own thing, ran into Martin, and was attacked by him. Rather, we know from the recorded phone call that Zimmerman followed Martin for at least two minutes in his car, at which point Martin ran away and Zimmerman got out of the car and began to follow him (per http://en.wikipedia.org/wiki/Shooting_of_Trayvon_Martin which has the audio recording). Under Florida law (http://law.onecle.com/florida/crimes/784.048.html), Zimmerman's behavior up to that point amounts to at least harrassment, and arguably aggravated stalking; it was certainly reasonable for Martin to believe that Zimmerman, through his actions alone, presented a credible threat to him.

Whether Martin was a peaceful person or not is thus (IMHO) mooted by the undisputed fact that Zimmerman was chasing him. Running away from another person is the exact opposite of an aggressive posture. Pursuing a person who is running away, by contrast, places the object of pursuit in a defensive posture. One could certainly argue that when Martin approached Zimmerman's car to 'check [him] out' and then ran away, that he had misapprehended Zimmerman's lawful intentions. But when Zimmerman got out of car and started running after him, that could only be interpreted as a threat. The act of pursuit made the situation into a conflict, in which Zimmerman was the aggressor.

It's worth considering what the outcome of this would have been had Zimmerman not shot Martin as he did - ie, supposing Martin had punched Zimmerman, knocked him down and straddled him as alleged by Zimmerman but that the police had shown up and stopped the fight before it went any farther. First, Martin would have have been able to argue that he was standing his ground in response to an unprovoked assault by Zimmerman; and second, that if Zimmerman had been convicted of aggravated stalking (and his behavior definitely constituted the elements of that crime: 1) wilful 2) malicious 3) repeated following, and 4) making a nonverbal threat placing the target in reasonable fear for his safety), then simply by virtue of carrying a weapon during the commission of that crime, he would have been subject to a mandatory minimum sentence of 10 years (http://law.onecle.com/florida/crimes/775.087.html).

Second (and this is more abstract), whatever the contents of Martin's phone, they were not known to Zimmerman at the time of their interaction. So they could not have had any bearing on Zimmerman's assessment of Martin. In other words, it would make no logical to sense to say 'Z was afraid of M because M was the sort of person who talked about fighting and trading firearms' - you're inviting the jury to consider knowledge after the fact as an input to Zimmerman's self-defense claim.

Now it might seem like the prosecution is doing that with regard to Zimmerman's past history of studying criminal justice and so on - but that's part of the prosecution's job in terms of demonstrating motive and prior knowledge. The prosecution is not attributing such insight to Martin, who knew only that he was being followed by a stranger in a vehicle. There's no requirement for the prosecution in a homicide case to limit itself to the information that was available to the victim at the time of the incident (otherwise you'd be able to get away with murder as long as the victim were surprised).

Almost universally in American law, the legitimate use of force in self defense can be summed up as "meeting force with force." Merely pursuing someone is not even assault and committing battery in response is thus unlawful. That is to say, Martin could not have lawfully attacked someone who was merely pursuing him. It would only be lawful self-defense on Martin's part if he was repelling physical violence (say, a punch or a kick) initiated by Zimmerman with equal force.

Again, though you may have a moral objection to how the law assigns blame here, that doesn't change the law.

Also, it's not an undisputed fact that Zimmerman was chasing Martin. Zimmerman, for one, disputes that. He claims that he got out of the car to see the street sign and then later tried to get a better view of where Martin went. Zimmerman claims he was attacked as he was walking back to his car. You don't have to believe Zimmerman, but the evidence presented to rebut his claim was hardly conclusive.

And yes, Zimmerman totally had no idea what was on Martin's phone and so the evidence is of absolutely no bearing on what Zimmerman thought of Martin. However, Zimmerman claimed that he was attacked by Martin. Nobody saw the beginning of the confrontation, so the only word we have is Zimmerman's. The prosecution called Zimmerman a liar on this point, so the evidence could show violent tendencies on Martin's part, bolstering Zimmmerman's story. It's not direct evidence and it's certainly prejudicial against Martin, but the defense certainly had the right to try to use it.

It's unclear what Zimmerman found suspicious about Martin's behavior besides his looking around as he walked down the street.

pursuing someone is not even assault

I disagree. You're arguing that someone who wasn't engaged in any criminal activity should be OK with kerb-crawling followed by foot pursuit. I would not be OK with someone following me down the street in such fashion.

Also, it's not an undisputed fact that Zimmerman was chasing Martin. Zimmerman, for one, disputes that.

The police dispatcher asks him whether he was following Martin and Zimmerman replied in the affirmative. This is just a fact. From the transcript of his call:

Dispatcher: Are you following him?

Zimmerman: Yeah.

I'm inclined to give his words on tape during the actual incident much greater weight than whatever a posteriori account he offered afterwards. After all, he wasn't on the hook for a homicide at the time he got out of the car.

What's scary are the number of everyday cases that don't attract major media attention where this has almost certainly happened without anyone ever knowing.

Whether Trayvon Martin was a peaceful person or not is irrelevant, there are no direct witnesses of the actual fight between him and Zimmerman and Martin had definite reason to fear for his own safety that night. This evidence seeks to imply racist stereotypes of black men being hyper-aggressive.

It's my opinion that if a white person had those photos on their phone, it would count negatively against a claimed peaceful character as well.

Unfortunately whether Martin was peaceful or not is absolutely not irrelevant. An important part of a trial like this is character construction / deconstruction by the prosecution and defense.

I suggest that it is. Let's agree you are a peaceful person; now imagine the following sequence of events, which I've tried to present in the most neutral terms possible.

a. You are walking along the street, at night, talking to someone on the phone.

b. You notice me following you, driving my truck at walking pace, for at least a full minute - half a block, probably.

c. You pause and stare at me. I stare back. You see I'm also on the phone.

d. You approach my vehicle a bit more closely.

e. Something makes you decide to turn and begin running away from me.

f. You hear me get out of my truck and start running after you.

Now, just answer me one question: how would you describe your situation at this point?

Should their photos be allowed into evidence? I.e. should the jury be allowed to consider: 1) their support for a hardline right-wing sheriff; and/or 2) their membership in an armed anti-immigrant organization? Or would that bias the jury?

I get that you're trying to pose the question of whether the homicide victim was also an aggressor, but if so we need to include the context that the person in question was fleeing the defendant when the alleged aggression took place.

If I chase you down the street for no good reason, and you turn around and punch me in the nose, who's at fault?

It has absolutely nothing to do with Martin being black or white or any other color, nobody said the missing information is relevant because Martin was black (and that fact was obvious from the start, so nobody in his right mind could claim there's some new information there) - the claim was that the information was relevant because Martin allegedly had closer relation to violence and firearms that was previously known. Nobody ever claimed that Martin was aggressive because he was black. The racism charge is pure bullshit. It is a fallacy to claim that it is always racist to say some particular black man is violent, because it "implies the stereotype". Well, some people are violent, and some black people are too - and the question was not whether Martin was black and thus violent (it is obvious he's black but that says nothing of him being violent) but whether Martin was violent regardless of him being black. And the data in the phone was relevant to that. Exactly because it is not imply that Martin was violent just from him being black, we need some evidence beyond that to figure out if he was - and the phone data is that evidence.

Are you arguing that the judge was wrong not to let evidence of Zimmerman's violent past be introduced?

Moreover, Angela Corey specifically claimed the prosecution does not have to disclose such evidence until the actual trial and can submit affidavit of probable cause based on half-truths, like it's some kind of poker game. Looks like she went further and did not disclose some of the information even after the trial started, which is clearly against the law. Moreover, if the verdict were different, it would most probably be a base for an appeal and good chance for the verdict to be thrown out due to prosecutorial misconduct and possibly another trial arranged, at great cost to both taxpayers and all participants. It is not a behavior that one has to condone in prosecutors, regardless one's opinion on the merits of the case. Even guilty ones should be prosecuted cleanly, in fair trial, not by violations of the laws and prosecutorial dirty tricks.