Should all homicides require an affirmative defense to not be manslaughter or murder?

In then context of everything else that was written in the OP (examples are usually given to clarify intent), it seemed clear to me that the OP was talking about requiring affirmative defenses like self defense rather than requiring the prosecution to prove lack of self defense as a defense.

Classy…

Hmm…based on the above, and this:

…perhaps we can add you to the “almost nobody here” who “seems to know wtf they are talking about”.

  1. There are no elements of homicide, because homicide is not a crime.

  2. If the state has proven murder, then a self-defense claim cannot succeed. Murder precludes self-defense.

  3. Murder and homicide are not the same thing. It’s crucial that you understand this for this discussion to amount to anything.

As above; no, they wouldn’t be trying to prove the murder was justified; murder cannot be justified. Homicide can.

Several people have pointed out the basic criticism of the idea: it shifts the burden of proof from the state to the accused, which is problematic: the state has far more resources to throw at the case; it makes false convictions more likely; and it’s at odds with the concept of “proof beyond a reasonable doubt” that underpins our system of criminal law.

Furthermore, why should a defense of self-defense be treated any differently than any other defense? If the accused claims that they were a hundred miles away at the time of the killing, do we demand that they prove they were, or demand the prosecution proove that they were not? If they claim the killing was accidental, likewise, it’d be up to the state to prove that it wasn’t. Is there any reason, beyond antipathy for George Zimmerman, to single out one factor that proves innocence and subject it to these additional hoops?

“We used to do it this way” is not, by itself, an argument. What are the merits of the idea?

That doesn’t sound like a bad idea; and indeed that is the rule in some states.

Zimmerman started a violent confrontation with Martin that resulted in Martin being killed. Zimmerman’s defense rested on the claim that he was in fear for his life, but his admitted actions make it clear that he was not in fear for his life (or at least, he was not behaving in a manner consistent with a reasonable and sane person in fear for his life) at the time that he started the confrontation. He might well have become fearful at some point during the confrontation, but he has nobody to blame for that but himself, as Martin had the right to defend himself.

In Zimmerman’s account, he did not start a violent confrontation with Martin; rather, he claims Martin started a violent confrontation with him. Thus, his account alone does not support a charge of murder.

The evidence at trial did not support this conclusion.

Zimmerman began following Martin. That is not violent, and there was no evidence adduced that Zimmerman was the first to add violence to the mix.

The evidence at trial did not support the conclusion you suggest.

Zimmerman’s claim that he was in fear for his life after Martin struck him.

Zimmerman’s “start” of the confrontation was his decision to exit his truck and follow Martin, and he did not claim to be in fear for his life at this time. There is no contradiction here; your phrasing suggests one.

Martin had the right to defend himself against physical attacks, to be sure. But no evidence was adduced at trial that Zimmerman was the initiator of such an attack.