Pennsylvania was the first state to differentiate the crime of "murder" into degrees based upon the culpability of the perpetrator. See, e.g. Joshua Dressler, Criminal Law: Cases and Materials 231-32 (4th ed. 2007) ("Prior to the recodification effort begun by the Model Penal Code, most American jurisdictions maintained a law of murder built around . . . common law classifications. The most significant departure was the division of murder into degrees, a change initiated by the Pennsylvania legislation of 1794."). Dressler goes onto explain that "[o]ther states followed the Pennsylvania practice until at one time the vast majority of American jurisdictions differentiated degrees of murder and the term 'first-degree murder' passed into common parlance." Id.</ref>
In the Commonwealth of Pennsylvania, common law felony murder was codified as "Murder of the Second Degree."[1] The statute provides that "[c]riminal homicide constitutes murder of the second degree when it is committed while defendant was engaged as a principal or an accomplice in the perpetration of a felony."[2]
The Pennsylvania formulation narrows the doctrine. Indeed, "Perpetration of a Felony" is statutorily defined as
A killing caused during the perpetration of a felony that is not otherwise listed in § 2502(d), i.e. aggravated assault, would be charged as Murder of the Third Degree or as a less culpable homicide provision, e.g. 18 Pa.C.S.A. § 2503 (Manslaughter).