An affirmative defense is a claim by a defendant in a trial that, while the accusations of action may be true and proven, the reasons behind them negate or partially negate the crime. Affirmative defenses contrast with negative defenses, which assert that a crucial part of the accusation is incorrect. There are many different types of affirmative defenses, including self-defense, insanity, accord and satisfaction, duress, and contributory negligence.
Though most laws provide absolutes, most legal systems make allowances for the fact that technically criminal actions may not be actually criminal in some circumstances. Self-defense affirmative defenses argue that while the defendant broke the law, it was with the reasonable and honest belief that his or her life was at stake. For example, a woman who shoots and kills her husband after he pulls out a weapon and tells her he is going to kill her and her children might be able to enter a plea of self-defense. Like most affirmative defenses, self-defense claims argue that the reasons behind the actions justify or excuse the behavior that might otherwise be considered criminal.
Some affirmative defenses, such as pleas of insanity, argue that the accused defendant is incapable of knowing or understanding the law, and thus cannot be fairly held to its requirements. Insanity defenses may not fully excuse a crime; clearly, if a person is proven insane enough to commit a criminal action, he or she may be seen as a danger to society. This type of defense is often used to lower or alter the penalties for a crime, such as removing special circumstance charges that could lead to the death penalty, or to allow a judge to send the defendant to a mental health institution instead of jail.
Affirmative defenses are frequently used in civil as well as criminal law. There are many different affirmative defenses that may be appropriate for civil cases, including accord and satisfaction, and contributory negligence. Accord and satisfaction occurs when a defendant discharges a contracted debt by agreeing to pay his lender a mutually acceptable amount, even if it is less than the originally specified amount. For instance, if a homeowner loses his job before he can pay a landscape architect for a $7,000 US Dollar (USD) job, the two might work out a new contract that allows the homeowner to discharge the debt with a one time payment of $4,500 USD. If, after receiving this payment, the landscape architect then decided to sue the homeowner for breaching the original contract, the homeowner might respond with a claim of accord and satisfaction.
Contributory negligence occurs when a defendant proves that a plaintiff was partially responsible for his own predicament. If a family sues a school district because their child slipped and fell on a newly-mopped floor, the school might be able to claim contributory negligence if it can be shown that the child was running through the halls and ignored “wet floor” signs. Contributory negligence may serve to lessen the amount of a claim or charge, or may be enough to have a case dismissed altogether.
Though affirmative defenses can be very successful, they often turn a case around by placing the burden of proof on the defendants. Normally, it is the job of the plaintiff to prove the guilt or responsibility of the defendant in a case. By claiming that the reasons behind the action excuse the crime, the defendant must then give compelling evidence that supports his or her claim in order to avoid conviction or damages.