The Australian legal system
Foundations
Australia is a federation under the Constitution, with a constitutional monarchy and parliamentary government. Its legal system is a common law system: judge-made law (case law) operates alongside legislation. Legislation made within power prevails over inconsistent common law. The rule of law means government action needs legal authority and is reviewable. The separation of powers divides legislature, executive and judiciary; at Commonwealth level Chapter III courts exercise judicial power, though the states do not have a strict separation. Responsible government makes the executive answerable to parliament.
Courts and precedent
The High Court is the apex. Below it are federal courts and state/territory courts with defined jurisdiction. Precedent means a ratio decidendi of a superior court in the same hierarchy binds lower courts. Obiter dicta are persuasive only. Courts may distinguish cases on material facts; the High Court may overrule its own earlier decisions.
Criminal and civil proceedings differ: criminal prosecution carries the burden on the prosecution and proof beyond reasonable doubt; civil cases use the balance of probabilities.
Traps and worked example
A common trap is treating “common law” as only one thing; it can mean judge-made law or the legal tradition. Another is assuming all remarks in a judgment bind. Worked example: the NSW Supreme Court states a ratio; it binds the NSW District Court, but not the Victorian Supreme Court. On appeal, the High Court could overrule it. Rule of thumb: ask whether the court is in the same hierarchy and lower, and whether the statement was necessary to the decision.