Criminal Law and Procedure
Elements and defenses
Most offenses require actus reus (the prohibited conduct) plus mens rea (a culpable mental state: intentionally, knowingly, recklessly, negligently). Strict liability offenses dispense with mens rea, usually for regulatory matters. Causation links conduct to harm (actual and proximate). Defenses include justification (self-defense, necessity, consent) and excuse (insanity, duress, infancy, mistake of fact). Attempt requires intent plus a substantial step; conspiracy requires agreement plus intent; complicity requires assistance with intent.
Procedure and rights
Criminal procedure covers arrest (probable cause), search and seizure (warrants, exceptions such as consent, plain view, incident to arrest), interrogation (right to silence and counsel), charging, bail, trial rights (public trial, jury, confrontation, effective counsel), and sentencing. The exclusionary rule may suppress evidence obtained unlawfully. Double jeopardy bars retrial after acquittal; burden of proof rests on the prosecution throughout.
Traps
- Confusing mistake of fact (often a defense) with mistake of law (rarely a defense).
- Treating motive as an element; it is evidence, not an element.
- Mixing attempt (no completed crime) with completed offense.
- Assuming silence is admissible; it may violate the privilege against self-incrimination.
- Confusing acquittal (factual innocence finding) with dismissal (procedural termination).
Rule of thumb
For any offense, list the elements first, then test each against the facts; a missing element defeats conviction.
Worked example
A defendant takes a wallet believing it is her own. The actus reus of theft is present, but the honest mistake of fact negates the intent to permanently deprive, so mens rea fails and the charge does not stand.