Self-defense, Australian style

By now, most people have seen, or at least heard of, Australian internet sensation Casey Heynes.  But in case you haven't, Casey is a young, well-spoken Aussie lad that was bullied by other school children for years.  In interviews, Casey described the bullying as both verbal and physical, and he said that it was the rare day that he wasn't struck by other kids.  But watch the following clip and see what happened when Casey, the portlier of the two chaps, finally said "enough is enough."

Youtube has deleted the video, but it can still be found on numerous websites, including this one: http://www.break.com/usercontent/2011/3/14/casey-got-bullied-2023232  

Now, assume that these two combatants were young adults instead of children, and that this happened in the United States.  Further assume that the bully (the loser of the fight) went to the police, and the local prosecutor decided to charge Casey (the winner of the fight) with battery.  Would a jury consider Casey's actions to be in self-defense? 

I think the answer is: yes.  A typical self-defense statute might permit a defendant to use reasonable force to terminate an unlawful interference with his person.  In this case, even putting aside the long history of bullying, Casey seems to be responding largely in a tit-for-tat manner, and he stops once the bully is on the ground.  Also, Casey's reaction seems to be in direct response to an ongoing threat; that is, it's not a delayed reaction that is meant as "pay back" for a past assault.  And most laws wouldn't require Casey's reaction to be the best course of action in hindsight; rather, the judge would likely tell the jury to assess things from the perspective of the defendant at that point in time.

But despite my argument on behalf of the defense, in my experience prosecutors have a simpler rule: forget the details, and just prosecute the winner of the fight.  And on the flip-side, a prosecutor would argue that Casey's reaction wasn't reasonable given their size differential.  Fortunately, I have had tremendous success in obtaining not guilty verdicts in these types of cases; however, prosecutors can cost defendants a great deal of time, their mental health, a temporary loss of freedom, and a lot of money in the process.

I'd be interested in responses from other defense lawyers to get their views on this type of case.  And, granted, most fights aren't caught on video (like this one was by the bully's friends who then kindly posted it to youtube), so maybe I'm over-simplifying what I perceive to be a prosecutorial policy of charging the winner of the fight.  Maybe some district attorneys out there can shed some light on how they deal with these types of cases when they land on their desks.