The Supreme Court has created a two-part test to determine when the death penalty is an appropriate punishment for felony murder.
[10] In California, examples of felonies that have been identified as "inherently dangerous" in the abstract include kidnapping and arson of a motor vehicle.
Under the complicity doctrine, an individual who is a cofelon to a felon who accidentally kills someone during an armed robbery, is also liable for that murder.
Examining nearly the same question a mere five years apart, the Court came to two different conclusions—that the Eighth Amendment allows the death penalty for felony murder in some cases but not others, and that the dividing line is the situation presented by Tison.
In response to Enmund, four states had modified their capital punishment statutes to reject the death penalty for murder committed in the course of a felony when the participant exhibited reckless indifference to human life.
By the time of Tison, some state supreme courts had expressly interpreted Enmund to allow the death penalty in these cases.
"The jury... is a significant and reliable objective index of contemporary values because it is so directly involved" in the criminal justice system.
In Enmund the Court recited that of 362 appellate decisions since 1954, only 6 involved a death sentence for a nontriggerman convicted of felony murder, and all 6 executions took place in 1955.
Faced with the objective evidence suggesting that legislatures and sentencing juries did not uniformly reject the death penalty for all defendants convicted of felony murder, the Court had to limit the death penalty to a discrete and narrow category of felony murder defendants based on its estimation of which category would best effectuate the goals of retribution and deterrence.
In Woodson v. North Carolina,[17] the Court had struck down a mandatory death penalty statute because it failed to provide for individualized consideration at sentencing.
The rule fashioned by Enmund and Tison accommodated this concern by ensuring that only felony murder defendants who had a sufficiently culpable mental state received the death penalty.
In an earlier case the Court had remarked that "capital punishment can serve as a deterrent only when murder is the result of premeditation and deliberation."
"A narrow focus on the question of whether or not a given defendant intended to kill... is a highly unsatisfactory means of definitively distinguishing the most culpable and dangerous of murderers."
In the Court's estimation, "reckless indifference to the value of human life may be every bit as shocking to the moral sense as an intent to kill."
If the death penalty is to be reserved for the worst murderers, Brennan believed in maintaining the distinction between an intentional act and a reckless one.
Because Enmund had not intended to kill the Kerseys, the Court had struck down his death sentence as not measurably contributing to either the goal of retribution or of deterrence.
[6] Scholars typically rationalize the felony-murder rule in four different ways: deterrence, transferred intent, retribution, and general culpability.
Opponents of the retributivist rationale argue that it is "primitive" and "simple", that it lacks nuance in terms of the felon's culpability and that it unjustifiably removes the mens rea element of the crime in question.