Criminal Law and Procedure
Elements and burdens
Every offense is a set of elements the state must prove beyond a reasonable doubt: the act (or legally required omission), the mental state, causation, and any attendant circumstances. Recite the elements before writing a report, because charging decisions and plea outcomes turn on them.
Standards of proof
Distinguish reasonable suspicion (articulable facts plus rational inferences that criminal activity may be afoot-enough for a stop or frisk) from probable cause (facts that would lead a reasonable officer to believe an offense has been or is being committed-enough for arrest or a warrant). Neither demands certainty, but probable cause is more than suspicion and far less than proof beyond a reasonable doubt.
Fourth Amendment framework
Warrantless searches are presumed unreasonable unless an exception applies: consent, search incident to arrest, automobile, plain view, exigency, inventory, and Terry frisk. Scope limits matter-a frisk is for weapons, and a search incident to arrest reaches the person and the area within immediate control.
Interrogation
Miranda applies to custodial interrogation: custody plus questions reasonably likely to elicit incriminating responses. Booking questions, spontaneous statements, and ordinary roadside questioning do not require warnings. A waiver must be knowing, voluntary, and intelligent, and an invocation must be honored.
Trap: confusing "detained" with "in custody" and assuming Miranda is required for field sobriety tests or basic traffic questions. Rule of thumb: articulate facts, not conclusions-"I smelled alcohol and saw bloodshot, watery eyes" beats "he seemed drunk."
Worked example: An officer stops a car for speeding, then smells alcohol and sees slurred speech and fumbling hands. Speeding supplied reasonable suspicion; the observations supply probable cause for a DWI arrest. Miranda applies only once custodial interrogation begins.