Notes on Accomplice Liability and Mens Rea

Aiding and abetting is best thought of as a separate route to liability for a crime, given that the defendant did not commit the crime themselves. At the same time, statutes governing accomplice liability feature the classic components of all crimes: an actus reus and a mens rea. In order  to convict, the state must prove beyond a reasonable doubt that:

1. The accused aided the principal actor, and
2. The accused did so with the requisite mens rea. 

This can result in surprising outcomes, even if consistent with blackletter law. For example, an accomplice can be convicted even if the principal is found not guilty of the target offense. 

Consider the following hypothetical:

Two men engage in a drive-by shooting. The driver and principal perpetrator starts a confrontation with a group of men standing on the side of the road at an intersection, fires multiple rounds at them, killing one and wounding two others. The principal’s passenger also pulls out a firearm and discharges multiple rounds, but does not hit any of the intended targets. The two men are arrested and tried together as co-defendants.

The principal perpetrator is charged with murder and two counts of attempted murder. The passenger is charged with aiding and abetting murder along with two counts of aiding and abetting attempted murder. At trial, the principal perpetrator testifies his vehicle had been shot at in the same intersection earlier that day, and he believed if he didn’t fire his weapon, the men on the street corner were going to shoot and kill him. The trial court refused to add a jury instruction for “unreasonable self-defense,” which would have allowed the jury to find him guilty of the lesser offense of voluntary manslaughter. The two men are convicted on all counts.

On appeal, now with separate lawyers, the principal perpetrator has his conviction overturned and is granted a new trial where he is entitled to assert the partial defense of “unreasonable self-defense.” Assume the new jury trial results in him being convicted of the lesser offenses voluntary manslaughter and two counts of attempted voluntary manslaughter.

What should happen with his former co-defendant - the passenger who was convicted of aiding and abetting of one count of murder, and two counts of aiding and abetting attempted murder? Should he likewise have his conviction overturned, given that the perpetrator is guilty only of a lesser offense? Or should his original conviction be upheld? See People v. McCoy, 25 Cal. 4th 1111, 24 P.3d 1210 (2001).

How might the following statement of the law of aiding and abetting inform your response:

“First, an aider and abettor with the necessary mental state is guilty of the intended crime. Second, under the natural and probable consequences doctrine, an aider and abettor is guilty not only of the intended crime but also for any other offense that was a "natural and probable consequence" of the crime aided and abetted.” Id. at 1117, 24 P.3d at 1213.