Everything You Need to Know About Affirmative Defense

Jul 23, 2019 | Criminal Defense

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An affirmative defense, also called a justification or excuse defense in the context of criminal charges, is defined as a fact (separate from any facts brought forward by the plaintiff or prosecutor) that, if proven to be true by the defendant being accused, defeats or mitigates the legal consequences of the crime. This means that an affirmative defense changes the context of the crime committed, and the result is that the standard legal punishment for the crime may not be appropriate.

The process of conducting an affirmative defense is as follows: the defendant must concede that he/she committed the crime or crimes, but prove with facts that there were extenuating circumstances that either excuse or explain why they would have committed them. Usually, affirmative defenses result in less stringent repercussions (as long as the defendant can prove that circumstances can explain his or her behavior).

In criminal prosecutions, the following are examples of affirmative defenses: self-defense, insanity, and the statute of limitations.


1. Self-Defense

One of the most common affirmative defenses is “self-defense.” Simply put, if a defendant can show that he or she had an honest and reasonable belief that another person’s use of force put their own life in danger (such that they could have been injured or killed if they had not acted accordingly), the defendant may not be charged with the usual punishment for crime. The defendant must prove that the other person’s actions were unlawful and that their actions were necessary for self-preservation and protection.


2. The Insanity Plea

Another common affirmative defense is called the insanity plea, whereby a defendant must prove that he or she was not able to act in alignment with the law because a mental illness–at the time the crime was committed–prevented him or her from understanding the nature of the crime. The defendant still must acknowledge that the crime happened, but that he/she was unaware of either the crime itself or its repercussions due to mental incapacities. In some cases, the insanity plea can be very difficult to prove.


3. Statute of Limitations

If the plaintiff or prosecutor has waited a certain amount of time before coming forward with the accusation, the defendant can claim an affirmative defense under the “statute of limitations.” These time limits vary by state.




The first, most important step to take if you are wondering whether an affirmative defense might be applicable to a lawsuit you are involved with is to consult a criminal defense attorney. A criminal case involving an affirmative defense is never straightforward, and a good defense case lawyer will help sort through all the evidence to help you determine what is reasonable, feasible, and lawful.

Before hiring an attorney, make sure to do some research on their relevant experience, since this will be critical in whether they will be helpful to you. Specifically, look into how much time the individual has spent in the courtroom, how many cases he or she has taken on, how many have involved affirmative defense, and how many they have won. Doing your research upfront will help ensure that you have the best chance of making a compelling case in court!