10/26/2014: "I'm guilty? Say what?!"
Did you know that self defense is an affirmative defense?
You're admitting you commited a crime, but have good reason not be held accountable for it.
According to the Black's Law Dictionary definition, affirmative defense is "[a n]ew matter constituting a defense; new matter which, assuming the complaint to be true, constitutes a defense to it." A more expanded explanation notes that it is "A defense in which the defendant introduces evidence, which, if found to be credible, will negate criminal or civil liability, even if it is proven that the defendant committed the alleged acts."
In Maryland, there are also the concepts of "perfect self defense" and "imperfect self defense", which relate especially to causing the death of the other individual. Five requirements must be satisfied to meet the standard of "perfect self defense", which can be used as a full defense of the actions. "Imperfect self defense", however, relates to the belief by the defender that his actions were reasonable, although they do not appear so to an outside observer. Imperfect self defense mitigates the charge, it does not negate it.
Self defense is an affirmative defense. You're admitting to having committed a crime, but justifying why you did so.