The Constitution, Federalism and the Division of Powers
Core concepts
The Commonwealth Constitution is a written, rigid, federal document entrenched by section 128 and interpreted by the High Court. Know federalism: powers are divided between Commonwealth and states. Exclusive powers belong to the Commonwealth (section 52, section 90 customs and excise); concurrent powers are shared (section 51), with Commonwealth law prevailing to the extent of inconsistency (section 109); residual powers remain with the states. Understand the heads of power, especially the corporations power, external affairs power, race power and defence power, and how expansive interpretation has centralised power.
Doctrines to name
Explain characterisation (how a law is connected to a head of power), implied intergovernmental immunities and the Melbourne Corporation principle, the Engineers case ending reserved state powers, and the fiscal imbalance created by vertical fiscal imbalance and tied grants under section 96. Know the referendum process and why so few succeed.
Traps
Do not say the states have only the powers left over from the Commonwealth-residual powers are general, and states retain broad legislative competence subject to inconsistency. Do not confuse section 109 with invalidity: only the inconsistent part of the state law is inoperative, and it revives if the Commonwealth law is repealed. Do not describe the Constitution as listing all Commonwealth powers exhaustively without acknowledging interpretation.
Rule of thumb
Use the inconsistency flowchart: valid Commonwealth law? valid state law? direct or indirect inconsistency? If yes, state law inoperative to the extent of inconsistency.
Worked example
A state law imposing a licence fee that conflicts with a Commonwealth scheme may be inoperative under section 109 only to the extent of the conflict; the rest survives.