Common Law Terminology

At common law, courts recognized four different types of parties to a crime. Although most jurisdictions have since abolished these categories, courts still use the terminology, so it is important to know.

A principal in the first degree refers to the perpetrator of the crime: the person who actually commits the crime by her own hand, an inanimate object, or an innocent human agent.

A principal in the second degree intentionally assists the perpetrator of the crime in his or her presence as the perpetrator commits the crime, through physical conduct, psychological influence, or an omission. “Presence” can be actual or constructive: a lookout or a getaway car driver are both considered present during the crime. The conviction of a principal in the second degree depended on the conviction of the principal in the first degree, and a principal in the second degree could not be convicted of a felony of a higher degree than the principal in the first degree (with the limited exception of premeditated homicide).

An accessory before the fact provides the same kind of aid to the perpetrator as a principal in the second degree, but is not present at the moment the crime is committed.

An accessory after the fact helps a perpetrator avoid arrest, detection, trial, or punishment, with knowledge that he or she is helping a criminal.

An accessory could not be convicted of a felony of a higher degree than the principal—except for homicide, for accessories who premeditated and intentionally aided a heat of passion murder. Also, the accessory could not be tried before the principal or if the principal was acquitted, even if acquittal was due to insanity.

All parties to treason were considered principals, not accessories.

Charges had to be brought against the principal in the jurisdiction in which the crime was committed, and against the accessory in the jurisdiction in which the assistance took place. The indictment had to reflect whether the person was a principal or an accessory; if the indictment charged a defendant with being the principal, she could not be found liable as an accessory, and vice versa. However, a defendant indicted as a principal in the first degree could later be found guilty as a principal of the second degree.

Most jurisdictions today treat both principals in the second degree and accessories before the fact as liable for the crime under a theory of accomplice liability. Most jurisdictions do not consider accessories after the fact accomplices; instead, those who aid after the crime is committed are liable for a lesser offense such as MPC 242.3: “Hindering Apprehension or Prosecution.”

Innocent Instrumentality

An innocent instrumentality is an agent that cannot possess criminal culpability, such as a nonhuman agent (like an animal), an innocent person lacking specific intent, or an innocent person excused from liability because of insanity, coercion, or age.  A person who commits a crime through an innocent instrumentality is guilty as a principal in the first degree, not as an accomplice.

A nonproxyable offense is an offense that can only be perpetrated by a designated person and therefore cannot be committed through the use of an innocent instrumentality. For example, to commit perjury, the defendant must lie on the stand. If X deceives Y into giving false testimony that Y believes is true, some courts have found X can be guilty of perjury, while others have found perjury is a nonproxyable offense and cannot be committed through an innocent instrumentality like Y.

Common Law Actus Reus

An accomplice must assist the perpetrator of the crime through physical conduct, psychological influence (including incitement, solicitation, or encouragement), or an omission when there is a legal duty to act. Mere presence at the scene of the crime is not enough, although encouragement has been interpreted broadly so that presence coupled with anything else satisfies the actus reus requirement. For example, explicitly telling the perpetrator that one will not interfere and applauding the perpetrator have both been found to constitute encouragement.

The accomplice must in fact assist the perpetrator in the commission of the offense. For example, if the defendant says words of encouragement such as, “I won’t interfere as you commit the crime,” but the perpetrator does not hear, then the defendant is not guilty as an accomplice. Causation is not required; the accomplice’s aid does not need to be the “but for” cause of the crime.