If you've been charged with a crime, you ultimately have to decide if you're going to plead guilty or fight the charges.
If you decide to fight the charges and ask for a trial, you then have to decide -- along with your attorney -- what type of defense you should offer.
Your defense has to fit the facts of the case and your attorney cannot knowingly allow you to lie, or perjure yourself, on the stand -- so an "affirmative" defense may be offered.
This defense is a little risky because you basically agree that you did just what you are accused of doing. However, you're also offering a justification for your actions that excuses your behavior to the point that it is no longer a crime.
For example, here are some common defenses that you've probably heard of before that are considered affirmative:
1. Standing your ground
You generally have a duty to try to get out of a fight if you can -- even if that means running away. However, people aren't expected to flee their own homes to avoid a fight. If you assaulted a robber who was sneaking around your bedroom at night, the court is likely to agree that you had every right to defend your home and family.
2. Defense of self
Sometimes, you can't run from a fight. If, for example, you were literally backed into a corner and you came out swinging and happened to get the best of your opponent, you could still be charged with battery for beating him or her up. However, if he or she backed you in that corner with threats and either threw the first punch or put you in fear for your physical safety, you had a right to defend yourself.
3. Defense of others
Sometimes, you have a right to defend someone else who can't defend themselves. For example, if you see an elderly woman being robbed and beaten, and you knock her assailant down from behind with a bat, you could still end up charged with assault -- but your justification, or affirmative defense, would be that you were protecting someone else from harm when he or she couldn't do so him- or herself.
Discuss your criminal defense options with your attorney carefully before you decide to use an affirmative defense -- they often hinge on fine definitions of the law.
Source: FindLaw Blotter, "What Is an Affirmative Defense?," Stephanie Rabiner, Esq., accessed Nov. 17, 2017