Division of Powers and Federalism: WACE Year 12 Politics and Law
“Explain the division of powers in the Australian federation and analyse how section 109 resolves inconsistency”
The division of powers splits law-making authority between the Commonwealth and the states. Exclusive powers belong only to the Commonwealth, concurrent powers are shared, and residual powers stay with the states. When a valid state law clashes with a valid Commonwealth law on a concurrent matter, section 109 makes the Commonwealth law prevail.
What this dot point is asking
Federalism is the system that distributes power between a central (national) government and regional (state) governments, each with its own area of authority guaranteed by the Constitution. SCSA wants you to be able to classify powers accurately and explain how clashes are resolved, because this underpins nearly every Unit 3 question about Commonwealth and state power.
The three categories of power
Exclusive powers can only be exercised by the Commonwealth. Some are exclusive by express words and others by operation of the Constitution: coining money (section 115), customs and excise duties (section 90), and defence in the sense of raising military forces are the standard examples. The states cannot legislate in these areas at all.
Concurrent powers are shared by the Commonwealth and the states. They are mostly found in the section 51 list of heads of power, such as trade and commerce, taxation, marriage and divorce, postal services and corporations. Both levels of government can legislate, and in everyday life much law is made by both.
Residual powers are not mentioned in the Constitution and therefore remain with the states. Because the Constitution lists what the Commonwealth can do and leaves the rest to the states, areas such as criminal law, education, health services, public transport and land use sit with Western Australia and the other states. This is why criminal offences and school systems differ between states.
A system of government in which a written constitution distributes power between a central government and regional governments, so that each level has an independent and constitutionally protected area of authority.
Section 51 and the heads of power
Section 51 is the key provision. It grants the Commonwealth Parliament power to make laws "for the peace, order, and good government" of Australia with respect to a list of around 40 subjects. These are the heads of power. Crucially, the list is closed: if a subject is not in section 51 (or another granting section), the Commonwealth generally cannot legislate on it directly. This is why the meaning of individual heads of power, like external affairs in section 51(xxix) or corporations in section 51(xx), matters so much and is fought out in the High Court.
Section 109 and inconsistency
Because concurrent powers are shared, the Commonwealth and a state can pass laws that conflict. Section 109 resolves this: where a law of a state is inconsistent with a law of the Commonwealth, the Commonwealth law prevails and the state law is invalid to the extent of the inconsistency. Two points are commonly tested. First, both laws must be otherwise valid; section 109 does not give the Commonwealth any new power, it just decides which valid law wins. Second, inconsistency can be direct (the laws contradict each other) or indirect, where the Commonwealth law is intended to "cover the field" so that no state law can operate, even a complementary one.
A frequent exam trap is to say section 109 lets the Commonwealth override the states generally. It does not. It applies only where a valid Commonwealth law and a valid state law conflict on a concurrent matter. Residual powers are untouched by it.
Why federalism matters and how it has shifted
Federalism was a condition of the colonies agreeing to federate in 1901, protecting state interests through the Senate and the division of powers. Over time the balance has tilted toward the Commonwealth through broad High Court interpretation of heads of power, the Commonwealth's dominance of income tax since the 1940s, and the use of tied grants under section 96. A strong answer notes that vertical fiscal imbalance (the Commonwealth raises most revenue while the states deliver most services) gives Canberra leverage even in residual areas like health and schools.
A common task gives a fact scenario and asks you to apply section 109. Work through it in steps.
Step 1: Check that both laws are valid
Suppose the Commonwealth makes a valid law under section 51 (for example on a concurrent matter like trade practices) and a state makes a valid law on the same subject. Section 109 only operates when both laws are otherwise valid, so confirm validity first.
Step 2: Identify the type of inconsistency
Ask whether the laws directly contradict (you cannot obey both) or whether the Commonwealth law shows an intention to cover the field so that no state law can operate. Either form triggers section 109.
Step 3: Apply the rule
Where inconsistency exists, the Commonwealth law prevails and the state law is invalid to the extent of the inconsistency. The state law is not wiped out entirely, only the conflicting part.
Step 4: State the limit
Note that section 109 does not apply to residual powers and gives the Commonwealth no new power. The conclusion should make clear it resolves a clash, it does not create supremacy.
Most criminal law is a residual power belonging to the states, which is why offences and penalties differ across Australia. The Commonwealth only has criminal law power where it attaches to a head of power, such as offences against Commonwealth officers or under the external affairs or trade and commerce powers.
Exam-style questions
Questions in the style of SCSA exam questions on this dot point, each with a worked answer. They are written by ExamExplained unless tagged "Past paper"; the year shows the paper a question is modelled on.
WACE 2021-style12 marksExplain the division of powers in the Australian federation and analyse how section 109 resolves inconsistency between Commonwealth and state laws.Show worked answer →
A 12 mark response needs accurate classification of powers and a precise account of section 109.
Division of powers. Exclusive powers belong only to the Commonwealth (for example coining money under section 115, customs and excise under section 90). Concurrent powers are shared and mostly listed in section 51 (trade and commerce, taxation, marriage). Residual powers are not mentioned and stay with the states (criminal law, education, health, transport).
Section 109. Where a valid state law is inconsistent with a valid Commonwealth law, the Commonwealth law prevails and the state law is invalid to the extent of the inconsistency. Both laws must already be valid; section 109 grants no new power. Inconsistency can be direct (the laws contradict) or indirect (the Commonwealth law covers the field).
Analysis. Conclude that section 109 only resolves clashes on concurrent matters and does not touch residual powers, so it does not make the Commonwealth supreme in general. Markers reward accurate classification and the valid-laws point.
WACE 2023-style6 marksDistinguish between exclusive, concurrent and residual powers, giving an example of each.Show worked answer →
A 6 mark short answer needs three clear definitions, each with a correct example.
Exclusive. Powers only the Commonwealth may exercise, by express words or by operation of the Constitution. Example: coining money under section 115, or customs and excise duties under section 90.
Concurrent. Powers shared by the Commonwealth and the states, mostly in the section 51 list. Example: taxation, marriage and divorce, or trade and commerce.
Residual. Powers not mentioned in the Constitution that remain with the states. Example: criminal law, education or public transport.
Markers reward one accurate definition and a correct matching example for each category.