Section 2.4


Fundamentals of Criminal Law

Adam J. McKee, Ph.D.

Jack Brown, Ph.D.


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Justification Defenses

In a criminal prosecution, the state must prove that the defendant is guilty of the crime charged beyond a reasonable doubt. In practice, this means that the government must prove each element of the crime charged at the legally appropriate level. Most of the time, if the prosecutor successfully does this, the result is a conviction. It is possible, however, for the state to prove each element of the crime and the defendant still be acquitted. This can happen when the defendant successfully proves a defense.

The American legal system is based on the presumption of innocence. A defendant may not be compelled to testify against himself or herself, and the prosecution is required as a matter of the due process of law to establish every element of a crime beyond a reasonable doubt to establish a defendant’s guilt. This heavy prosecutorial burden also reflects the fact that a criminal conviction carries severe consequences and individuals should not be lightly deprived of their liberty. Insisting on a high standard of guilt assures the public that innocents are not being falsely convicted and that individuals need not fear that they will suddenly be snatched off the streets and falsely convicted and incarcerated.

The prosecutor presents her witnesses in the case-in-chief. These witnesses are then subject to cross-examination by the defense attorney. The defense also has the right to introduce evidence challenging the prosecution’s case during the rebuttal stage at trial. A defendant, for instance, may raise doubts about whether the prosecution has established that the defendant committed the crime beyond a reasonable doubt by presenting alibi witnesses.

a criminal defendant will be acquitted if the prosecution cannot prove every element of the offense beyond a reasonable doubt. In certain cases, the defendant can either deny that a criminal element exists or simply sit back and wait for the prosecution to fail in meeting its burden of proof. This legal strategy is sometimes referred to as either a denial of proof or failure of proof defense.

A defense can reduce the severity of the offense, or completely exonerate the defendant from criminal responsibility. If a defense reduces the severity of the offense, it is called an imperfect defense. If a defense results in an acquittal, it is called a perfect defense. The difference between the two is meaningful. A defendant who is successful with an imperfect defense is still guilty of a crime; a defendant who is successful with a perfect defense is innocent.  In addition, defenses can be classified by the grounds on which it is based. A defense must be based on specific grounds. If a defense is based on an issue of fact, it is a factual defense. If a defense is based on an issue of law, it is a legal defense.

Criminal law permits a number of affirmative defenses that can greatly reduce or eliminate altogether a defendant’s criminal liability. Criminal defenses can be divided into two major branches: Affirmative defenses and non-affirmative defenses.

Non-affirmative defenses attack the elements of the crime that the prosecution is trying to prove. For example, a defendant may raise an alibi defense where he states that he was not present when the crime occurred and thus could not have committed it. The big idea is that non-affirmative defenses attack the prosecutor’s proof. If a non-affirmative defense can cause the jury to have a reasonable doubt, then the defense has worked and the defendant will be acquitted.

When an affirmative defense is used, the defendant essentially admits guilt but offers an excuse or justification for his or her criminal actions. An affirmative defense is not connected to the prosecution’s burden of proof. When the defendant asserts an affirmative defense, the defendant raises a new issue that must be proven to a specified evidentiary standard. State statutes often specify whether a defense is affirmative. In most jurisdictions, the defendant must submit enough evidence to the trial judge to show that an affirmative defense possibly exists before the jury can hear the evidence for the defense. The requirement that this initial evidence must be submitted to the judge is called the burden of production.

Once the defendant meets this burden of production, the burden then shifts to the prosecution. The burden placed on the prosecution is much higher than that of the defendant. While the defendant does not have to produce a large amount of evidence, the prosecutor must counter the defense with evidence beyond a reasonable doubt that no legal defense exists.

Affirmative defenses can generally be divided into two categories: excuse defenses and justification defenses.

Excuse defenses involve situations where the defendant admits to committing the crime but claims that he or she is not blameworthy because of some extenuating circumstances, such as insanity or duress.  The defense of insanity, for example, does not seek to justify the violation of a law. Rather, the defense concedes that the violation is unjustified, but seeks to exempt the particular actor from criminal responsibility. A claim of justification maintains that the act is right; a claim of excuse acknowledges that the act s wrong, but argues that the actor is not personally responsible for having committed the act. Injuring an innocent person is wrong, but if the actor is insane, his condition precludes his being held responsible for the wrongful act.

Justification defenses involve situations where the defendant admits to committing the crime and that the action was appropriate under the circumstances surrounding the act. Normally it is criminal to cause the death of another living human being. If, however, the death comes about as the lawful execution of a death warrant, then the executioner is not held criminally liable because he or she is bound to cause the death by public duty. Similarly, if a police officer kills a person that is trying to stab him with a knife, then the killing is considered self-defense and so the officer is not criminally liable.  

A primary difference between these two major categories of defense is the particular focus of the defense. A defense based on justification focuses on the offense. A justification defense asserts that the defendant’s otherwise criminal actions should be legal rather than criminal because it supports a principle valued by society. A defense based on an excuse focuses on the defendant. An excuse defense asserts that even though the defendant committed the criminal act with criminal intent, the defendant should not be responsible for the criminal behavior.  

Modification History

File Created:  07/13/2018

Last Modified:  07/13/2018

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This work is licensed under an Open Educational Resource-Quality Master Source (OER-QMS) License.

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