Criminal law: general principles and offences
Criminal law: general principles and offences
This domain tests the building blocks of liability: legality, conduct, mental element, causation, participation, and defences. Apply the statute's definition, not moral disapproval.
Core rules
- Nullum crimen sine lege: an offence and penalty must exist in law before the act; analogy against the accused is barred.
- Actus reus requires voluntary conduct, sometimes an omission where a legal duty exists; causation must be factual and legal.
- Mens rea includes intent, knowledge, recklessness, or negligence as the definition requires; motive is generally irrelevant.
- Attempt requires a substantial step beyond preparation; complicity requires assistance or encouragement with the requisite mental element.
- Defences include self-defence, necessity, duress, minority, insanity, and mistake; excessive force can reduce but not always excuse.
- Concurrence requires the mental element to accompany the conduct.
Worked example
A pushes B during an argument; B falls, hits his head, and dies. A intended the push, not death. If the offence is intentional homicide, intent to kill is not proved; if the statute covers bodily harm causing death, the causal link and foreseeability of serious harm must be shown. The push is a factual cause, but legal causation may fail if B's fall was extraordinary.
Traps
Assuming intent to act equals intent to harm; ignoring omission duties; treating motive as mens rea; conflating attempt with preparation; overlooking proportionality in self-defence.