There are two basic types of defenses under Texas law, justifications and excuses. Justifications absolve a person of criminal responsibility even though they committed the crime. The most common example of this is self-defense. In a self-defense case the criminal act was committed, but the criminal act was deemed justified. Another general type of defense is an excuse. This occurs where a person’s culpable mental state was so severely affected by circumstances beyond their control that they are not held legally responsible for their actions. An example of this is duress. Duress occurs, for example, where a person commits a criminal act solely because they were threatened with death or serious bodily injury.
Justifications are found in chapter 9 of the Texas Penal Code and include public duty, necessity, self-defense, defense of others, and defense of property. The public duty defense is primarily intended for law enforcement and for those who have a duty to defend another based on a special legal relationship. The necessity defense applies when the actor reasonably believes the conduct is necessary to avoid a greater immanent harm. Self-defense cases are more common.
Self-defense may be used in response to deadly force or non-deadly force, but not in response to verbal provocation alone. Using non-deadly force in self-defense is legally justified when the act is something that an ordinary reasonable person would believe is immediately necessary under the circumstances, and when the actor believes the force is immediately necessary. Deadly force is legally justified only in response to deadly force, but non-deadly force is legally justified any time self-defense is justified. Much of the litigation in self-defense cases is over whether or not the actors’ use of force constitutes deadly force, and whether or not the alleged victim’s use of force constitutes deadly force.
The law regarding the use of force to protect third persons mirrors the law of self-defense. If the actor reasonably believes that the person he is defending would have the right to use the type of force used then the use of force is justified. Like self-defense law in Texas, there is no duty for either the third party or the actor to retreat before using force to defend another.
Non deadly force may be used to protect property to prevent trespass or unlawful interference with one’s property, or to recover property if the actor is in fresh pursuit of the thief. Deadly force may be used to prevent the commission of a burglary, robbery, theft during the nighttime, or vandalism during the nighttime, or to prevent a person from fleeing immediately after committing a burglary, robbery, or theft when the use of non-deadly force would expose the actor to a substantial risk of serious bodily injury.
Chapter 8 of the Texas Penal Code lists general defenses to criminal responsibility that are not justifications. These include insanity, duress, and entrapment. A person is not criminally responsible by reason of insanity when the actor didn’t know their conduct was wrong as a result of a severe mental disease or defect. Insanity is an affirmative defense which means the defendant has the burden of proving his insanity by a preponderance of the evidence.
Duress is also an affirmative defense to prosecution. Proving duress requires the defendant to prove that he was compelled to do the illegal act by force or threat of force. In a felony case the defendant must prove that he was compelled to do the illegal act by the threat of imminent death or serious bodily injury to himself or another. This defense is not available if the defendant knowingly placed himself in a situation where it was probable he would be subjected to the compulsion described above.
Entrapment occurs when the defendant was persuaded to do the criminal act by law enforcement in a manner that would persuade an ordinary person under the circumstances. Once the defendant shows that he was the target of persuasive police conduct the Court’s focus is directed at the police conduct itself and the question is whether or not the police conduct in question would persuade an ordinary person under the circumstances. Unlike other defenses the entrapment defense may be raised at a pretrial hearing.