Criminal defenses: Intoxication defense + Age of criminal responsibility

The age of criminal responsibility is the age below which a child is deemed incapable of having committed a criminal offence. In legal terms, it is referred to as a defense of infancy, which is a form of defense known as an excuse so that defendants falling within the definition of an "infant" are excluded from criminal liability for their actions, if at the relevant time, they had not reached an age of criminal responsibility. After reaching the initial age, there may be levels of responsibility dictated by age and the type of offense committed.

Under the English common law, the defense of infancy was expressed as a set of presumptions in a doctrine known as doli incapax. A child under the age of seven was presumed incapable of committing a crime. The presumption was conclusive, prohibiting the prosecution from offering evidence that the child had the capacity to appreciate the nature and wrongfulness of what they had done. Children aged 7–13 were presumed incapable of committing a crime but the presumption was rebuttable. The prosecution could overcome the presumption by proving that the child understood what they were doing, and it was wrong. In fact, capacity was a necessary element of the state's case. If the state failed to offer sufficient evidence of capacity, the infant was entitled to have the charges dismissed at the close of the state's evidence. Doli incapax was abolished in England and Wales in 1998, but persists in other common law jurisdictions.

In criminal law, the intoxication defense is a defense by which a defendant may claim diminished responsibility on the basis of substance intoxication. Where a crime requires a certain mental state (mens rea) to break the law, those under the influence of an intoxicating substance may be considered to have reduced liability for their actions. With regard to punishment, intoxication may be a mitigating factor that decreases a prison or jail sentence. Numerous factors affect the applicability of the defense.