Legal Definitions - right-and-wrong test

The right-and-wrong test is a legal doctrine used in criminal law to determine whether a person is criminally responsible for their actions. It is also known as the McNaghten rules, which were established in 1843 in England.

The McNaghten rules state that a person is not criminally responsible for an act if a mental disability prevented them from knowing either the nature and quality of the act or whether the act was right or wrong. This means that if a person did not understand what they were doing or did not know that their actions were wrong, they cannot be held responsible for a crime.

For example, if a person with a mental illness believed that they were killing a monster instead of a human being, they may not be held responsible for murder under the right-and-wrong test.

The right-and-wrong test is used in many federal courts and states in the United States. It only applies in cases where there is a "defect of reason, from disease of the mind," which includes congenital defects or traumatic injuries. If a defendant did not know what they were doing because of this defect, they are not guilty of a crime. Even if they knew what they were doing, they are not guilty if they did not know it was wrong because of the defect.

Overall, the right-and-wrong test is used to determine whether a person with a mental disability can be held responsible for a crime based on their understanding of their actions.