What is the factor that can reduce common law murder to manslaughter?

The factor that can reduce common law murder to manslaughter is adequate provocation. This concept is rooted in the understanding that certain emotional reactions to provoking actions can lead individuals to act in a way that is not premeditated. Under common law, if a person kills another in the heat of passion caused by adequate provocation, it can serve as a mitigating factor that reduces the charge from murder to voluntary manslaughter.

Adequate provocation must involve a situation that would cause a reasonable person to lose self-control. Common examples include circumstances in which the victim engages in behavior that is particularly egregious or offensive, such as infidelity or physical attacks. The law recognizes that such provoking actions can cause a temporary loss of reason and self-control, which is why the act is deemed less culpable than a murder carrying malice aforethought.

Effective application of this principle aims to consider the emotional state of the defendant, providing a more nuanced view of their actions that acknowledges human reactions to extreme stressors or provocations. Therefore, adequate provocation serves as a significant legal criterion to mitigate culpability in homicide cases.