Murder and manslaughter are both charges against a person who, by their actions, has caused the death of another person (or people). The essential difference between murder and manslaughter is that a person who knowingly and deliberately kills another person, they have generally committed murder, whereas a person who did not plan out the act in advance, or did not actually intend for death to occur, may be guilty of manslaughter instead. The precise distinction between murder and manslaughter differs according to legal jurisdiction; however, universally, manslaughter is considered a lesser charge and can be punished less severely than murder.
In general, the difference between murder and manslaughter, and the severity of the charge levelled against the guilty party, depends on their frame of mind at the time that the death occurred. A killing which the person deliberately plans and carries out – the technical term is “with malice aforethought” – is considered murder. In short, a person who deliberately and knowingly sets out to end another person’s life is guilty of murder.
In many countries, including the U.S., people may be accused of either first-degree or second-degree murder. When this distinction is made, it generally refers to the degree of premeditatedness. A person who lies in wait to ambush and kill someone, who murders a law enforcement official, and so on, is generally considered to have murdered in cold blood and is charged with first-degree murder. Where capital punishment is still used to punish murderers, particularly in parts of the United States, it is most commonly in connection with first-degree murder. In many cases (especially in the U.S.), a person who is committing a serious crime and kills a person while doing so is automatically considered to have committed a murder, whether they planned the killing or not.
Manslaughter, by contrast, refers to situations in which a person did not plan to or intend to kill, but did so nonetheless. In some jurisdictions, a person may be technically guilty of manslaughter – referred to as voluntary manslaughter – in a situation where they did have some intent to kill, but this intention is reasonably explained by complicating factors. For instance, in some jurisdictions a person who kills in self-defence may be found guilty of manslaughter if their use of force to defend themselves was legitimate, but the use of lethal force was plainly unnecessary. In other cases, a person may be found technically guilty of voluntary manslaughter rather than murder if they were found to have been provoked into losing control. The precise delineation between murder and manslaughter on these technical grounds varies considerably between different jurisdictions, including between American states.
In other cases, however, a clear charge of involuntary manslaughter can be laid. In such cases, one person has killed another without any apparent intention to do so, but in a way that makes them clearly responsible. Throwing debris into heavy traffic, for instance, may cause a fatal collision; in such a case, there might be no intent to cause harm to any particular person (it could have been a juvenile and incredibly irresponsible prank, for instance), but if harm did result (including death), the person throwing the debris would clearly be responsible. This is known as constructive manslaughter. Manslaughter may also be charged against a person who has a specific obligation (known as a “duty of care” in legal parlance) to help a person they realize is in life-threatening distress, and fail to do so, as well as (in certain cases) against people who cause death through a car collision while they are violating the traffic laws or driving under the influence of alcohol.
If you have specific legal questions about murder, manslaughter, or any other legal topic, you should discuss them with a lawyer, who can offer professional and qualified legal advice tailored to your specific situation.