What Are the Two Major Categories of Defense to Crimes?

Being charged with a crime can be a frightening and stressful experience. It’s vital to understand that under the law, you are presumed innocent until proven guilty. That means the prosecution must prove beyond a reasonable doubt that you committed the crime. One of the most important tools you have is the ability to raise legal defenses to the charges against you. Criminal defense generally falls into two major categories:

Justification Defenses

self defense

Justifications are defenses where, although the defendant admits to committing the act, the actions are deemed acceptable under the law due to the circumstances. This category includes defenses such as self-defense, defense of others, and necessity. These are not merely technical defenses but are rooted in the recognition that, in certain situations, the otherwise criminal actions are acceptable to protect oneself or others.


Self-defense is a fundamental legal doctrine that allows a person to use reasonable force to protect themselves from immediate and unlawful harm. The key elements involve proving the immediacy of the threat and the reasonableness of the force used. For example, in cases of assault, the defendant must demonstrate that they genuinely believed they were in imminent danger and that their response was proportionate to the threat faced. This defense is frequently utilized in cases ranging from simple assault to more severe charges like manslaughter or murder.

Defense of Others

This justification aligns closely with self-defense but extends the protection to another person under threat. Legally, a defendant can argue this defense when they intervene to protect someone else who is in immediate danger of harm. The legality of the force used hinges on its necessity and proportionality, similar to self-defense. This defense often plays a crucial role in incidents where the defendant acts to prevent an attack on a third party, demonstrating the societal value placed on protecting others.


The defense of necessity applies when a defendant claims that their illegal action was the only way to prevent a more significant harm. This requires demonstrating that the harm avoided was greater than the harm caused by the illegal act. Legal systems generally require that the situation involves an immediate, imminent threat with no lawful alternatives available. Common scenarios include breaking into a building to save someone from a life-threatening situation, such as a fire or other disaster.

For instance, our case results include scenarios where justifications played a critical role in defending our clients successfully against serious charges.

Excuse Defenses

silhouette of anonymous alcoholic person drinking behind bottles of alcohol

Excuses are defenses where the defendant argues that some personal condition or circumstance at the time of the alleged crime should excuse their behavior, making them not criminally responsible. This category includes insanity, duress, and intoxication defenses.


The insanity defense is a complex legal argument that hinges on the claim that at the time of the crime, the defendant was suffering from a severe mental disorder that impaired their ability to understand the nature of their actions or to differentiate between right and wrong. 

Legal systems generally apply stringent tests to determine the validity of this defense, such as the M’Naghten Rule, which focuses on the defendant’s understanding of their actions, or the Irresistible Impulse Test, which might consider the defendant’s ability to control their actions despite understanding their wrongfulness. Implementing this defense requires detailed psychiatric evaluations and often hinges on expert testimony to demonstrate the mental condition of the defendant effectively.


This defense applies when a defendant asserts that they were compelled to commit a criminal act due to an immediate threat of serious harm or death, either to themselves or to others. For duress to be successfully argued, the threat must be shown to be immediate, real, and unavoidable, with no reasonable opportunity to escape the situation. 

Importantly, duress is not a permissible defense for murder or other serious crimes in many jurisdictions, reflecting the principle that one may not save oneself by harming another. The key aspect of duress is the lack of free will in choosing to commit the act.


Intoxication as a defense is differentiated into voluntary and involuntary intoxication. Voluntary intoxication, where the defendant knowingly ingests a substance, rarely excuses criminal behavior but may be considered in cases requiring specific intent to undermine the requisite mental state. 

In contrast, involuntary intoxication, which occurs without the defendant’s knowledge or against their will, such as being drugged, can be a complete defense if it prevents the defendant from understanding the nature of their actions or forming the necessary intent to commit a crime. This defense must be substantiated with evidence that the intoxication was indeed involuntary and significantly impaired the defendant’s cognitive abilities.

For more detailed explanations and cases related to these defenses, visit this page.

Contact Our Criminal Attorney for a Free Consultation

If you find yourself in a legal situation where these defenses may be relevant, do not hesitate to contact us. Taking swift action to secure experienced legal representation is essential. Let Southwell Law, LLC assist you in navigating the complexities of your case and work towards securing a favorable resolution.

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