Ch. 5—Accomplice Liability

Accomplice Liability: accomplices are vicariously liable for the acts of the principal—equally as guilty as the principal in the eyes of the law.

Requirements

Actus Reus
- Material assistance of the principal (aid, encourage, procure, or facilitate).
- Mere presence does not establish actus reus—unless that presence is intended to and does encourage/aid the principal (see New Hampshire v. Merritt, 738 A.2d 343 (N.H. 1999)).
Mens Rea (Common Law)
- Intent to assist or encourage the principal,
- Intent that the principal actually commit the crime, AND
- The mens rea required of the underlying offense.
Attendant Circumstances
- The crime intended must actually occur (or be attempted, where attempt liability attaches).
Knowing assistance ≠ purposeful assistance: see Twitter, Inc. v. Taamneh, 143 S.Ct. 1206 (2023)—platform's general awareness that bad actors used its services was insufficient.

Principals
- In the First Degree — actually performs the actus reus.
- In the Second Degree — intentionally assists and is present; treated as accomplice.
Accessories
- Before the Fact — intentionally assists/encourages, not present; treated as accomplice.
- After the Fact — helps cover up; not an accomplice—distinct crime, no merger.

New Hampshire v. Merritt, 738 A.2d 343 (N.H. 1999) — actus reus; presence as encouragement.
Twitter, Inc. v. Taamneh, 143 S.Ct. 1206 (2023) — knowing vs. purposeful; conscious culpable participation.
Standefer v. United States — accomplice may be convicted even where principal acquitted (pp. 213–16).
People v. Soares — purpose to promote/facilitate (pp. 213–16).
People v. Kaplan — natural and probable consequences doctrine (pp. 216–19).
State v. Potts — limits on accomplice liability for unintended results (pp. 221–23).

Reading: pp. 193–95, 204–05 (MPC), 208–10, 213–37.