Party Liability

Question 1

R. v. Thatcher

Answer 1

Jury Unanimity: Jury does not need to agree on how accused participated (Principal vs Aider) as long as they agree he participated.

Question 2

R. v. Pickton

Answer 2

Aiding/Abetting Instruction: Jury can convict if satisfied accused was involved as either principal or aider.

Question 3

Dunlop & Sylvester v. The Queen

Answer 3

Mere Presence: Being present at crime scene is not aiding unless there is encouragement or legal duty to act.

Question 4

R. v. Greyeyes

Answer 4

Trafficking (Parties): Assisting a buyer can constitute aiding the seller if it facilitates the sale.

Question 5

R. v. Kirkness

Answer 5

Common Intention (s. 21(2)): Requires formed intention in common. Mere presence/assistance without common plan is insufficient.

Question 6

R. v. Logan

Answer 6

Attempted Murder (Parties): s. 21(2) usually uses objective foresight. EXCEPTION: Attempted Murder requires Subjective intent to kill.

Question 7

R. v. Duong

Answer 7

Accessory After Fact: Willful blindness to the principal’s crime is sufficient mens rea.

Question 8

R. v. Gauthier

Answer 8

Abandonment: To leave party pact: (1) Change intent, (2) Timely notice, (3) Unequivocal notice, (4) Reasonable steps to neutralize.

Question 9

R. v. Popen

Answer 9

Aiding (Omission): To aid by omission (e.g., failing to protect a child), there must be evidence the omission was done for the purpose of aiding the assault.

Question 10

R. v. JF

Answer 10

Conspiracy (Joiner): An accused can be a party to conspiracy if they aid/abet the formation of the agreement or help a new member join.

Question 11

R. v. Briscoe

Answer 11

Mens Rea for Aiding (Willful Blindness): The accused drove accomplices to a golf course where they raped and murdered a victim, but claimed he “did not want to know” their specific plans. The SCC held that the mens rea for aiding (s. 21(1)(b)) requires intent to assist and knowledge of the principal’s intention to commit the crime. Willful blindness (deliberate ignorance where one suspects the truth) satisfies this knowledge requirement.

Question 12

R. v. Nixon

Answer 12

Aiding by Omission (Duty to Act): A senior police officer stood by while a prisoner was beaten by other officers in a lockup. While “mere presence” is generally insufficient for party liability, the Court held that an omission constitutes aiding and abetting where the accused has a legal duty to act (e.g., a statutory duty to protect detainees) or where the failure to intervene is intended to encourage the offence.

Question 13

R. v. Helsdon

Answer 13

Subjective Mens Rea for Accessories: The Court rejected the argument that an aider/abettor could be convicted on an objective standard just because the principal crime was one of objective fault. The rule is that aiding and abetting (s. 21(1)(b)) always requires a subjective mens rea (actual knowledge and intent), regardless of the fault requirement for the underlying offence.