Changing the Constitution and the Federal Balance - TCE Legal Studies (Tasmania)
“Explain how the Constitution is changed through referendum under section 128 and how the balance of power between the Commonwealth and the states has changed over time.”
The words of the Constitution can only be changed by referendum under section 128, which requires a double majority: a national majority of voters and a majority of voters in a majority of states. Most referendums fail, so the balance of power has shifted mainly through High Court interpretation, financial control and use of the external affairs power, not through changing the text.
What this dot point is asking
This dot point asks you to explain the formal process for changing the Constitution and the informal ways the federal balance has actually shifted.
Formal change: section 128 referendum
The text of the Constitution cannot be changed by an ordinary Act of Parliament. Section 128 sets out a special process:
- A bill to alter the Constitution must be passed by an absolute majority of both houses of the Commonwealth Parliament (or by one house twice in certain circumstances).
- The proposal is then put to the people at a referendum.
- It succeeds only if it achieves a double majority: a majority of all voters nationally, and a majority of voters in a majority of states (at least four of the six states).
The requirement under section 128 that a referendum to change the Constitution must be approved by a majority of voters across the nation and also by a majority of voters in at least four of the six states.
Why most referendums fail
Of the 44 or so referendum proposals put to the people, only eight have succeeded. The double majority is demanding, because a proposal can win the national vote yet fail because it did not carry four states. Other reasons include bipartisan support being rare, voters tending to vote no when they are uncertain, and the difficulty of explaining complex constitutional change. A successful example was the 1967 referendum, which passed with overwhelming support and allowed the Commonwealth to make laws for Aboriginal and Torres Strait Islander peoples and count them in the census. A recent unsuccessful example was the 2023 referendum on an Aboriginal and Torres Strait Islander Voice to Parliament, which failed to gain a national majority or a majority of states.
Changing the words of the Constitution requires a section 128 referendum with a double majority. Because this is so difficult, the Constitution has been amended only a handful of times, and the federation has changed far more through interpretation than through formal amendment.
Informal change: how the balance has shifted
Even though the text rarely changes, the balance of power between the Commonwealth and the states has shifted markedly toward the Commonwealth:
- High Court interpretation: the court has read Commonwealth powers broadly. The Engineers Case (1920) rejected a narrow reading of Commonwealth power, widening federal authority.
- Financial dominance: since the Commonwealth gained sole control of income tax during the Second World War, the states have relied on Commonwealth grants under section 96, which often come with conditions. This is called vertical fiscal imbalance.
- External affairs power: by entering international treaties, the Commonwealth can legislate under section 51(xxix) on matters that would otherwise be state responsibilities, as seen in the Tasmanian Dam Case (1983), where the Commonwealth stopped a dam to honour a world heritage treaty.
Why this matters
These shifts show that a constitution can stay almost the same on paper while the real distribution of power changes significantly. For Tasmania, financial reliance on the Commonwealth and the reach of national laws affect how much genuine autonomy the state holds. As one of the smaller and less populous states, Tasmania benefits from the double majority safeguard, because its voters help decide whether four states approve a change, but it is also the most exposed to vertical fiscal imbalance, since it raises relatively little of its own revenue and depends heavily on Commonwealth grants. This tension between formal protection and practical dependence is a useful Tasmanian angle to bring into an answer.
A common task asks you to contrast formal and informal change. Work through it in steps.
Step 1: Set out the formal process
State that section 128 requires a bill passed by parliament, then a referendum, then a double majority (national majority plus four of six states) before the text can change.
Step 2: Show that formal change is rare
Explain that only eight of about 44 proposals have passed, because the double majority is demanding and bipartisan support is uncommon.
Step 3: Identify the informal mechanisms
Give the three drivers of real change: broad High Court interpretation (Engineers Case), financial dominance via income tax and section 96 grants, and the external affairs power (Tasmanian Dam Case).
Step 4: Reach the conclusion
Conclude that the federation has centralised toward the Commonwealth mainly through interpretation and finance, not through amending the words, so the live distribution of power differs from the unchanged text.
A common error is to assume the Commonwealth Parliament can amend the Constitution by passing an Act. It cannot. Only the people, through a section 128 referendum with a double majority, can change the text. Parliament can only put the question.
For exam answers, set out the section 128 process and the double majority, explain why referendums usually fail with a real example, then contrast this with the informal shift of power to the Commonwealth through interpretation, finance and external affairs.
Exam-style questions
Questions in the style of TASC 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.
Practice6 marksExplain the double majority requirement and why it makes constitutional change difficult.Show worked answer →
A 6 mark response needs the two parts of the double majority and the reason it is hard to satisfy.
The requirement. Under section 128, a referendum to change the Constitution succeeds only if it gains a national majority of all voters and a majority of voters in a majority of states, that is at least four of the six states.
Why it is difficult. A proposal can win more than half the national vote yet still fail because it did not carry four states. Smaller states can therefore block a change that a national majority supports. Add that bipartisan support is rare and uncertain voters tend to vote no.
Markers reward correctly stating both limbs (national majority plus four states) and explaining the blocking effect, ideally with the figure that only eight of about 44 proposals have passed.
Practice12 marksMost of the change to the federal balance has come without changing the words of the Constitution. Explain and analyse this statement.Show worked answer →
A 12 mark response needs the formal process, the informal mechanisms, and an analysis weighing them.
Formal change. State that the text changes only by section 128 referendum with a double majority, and that this has succeeded only eight times, so formal amendment is rare.
Informal change. Explain the three main drivers that have shifted power to the Commonwealth: High Court interpretation reading section 51 powers broadly (Engineers Case 1920); financial dominance through the Commonwealth's control of income tax and conditional grants under section 96 (vertical fiscal imbalance); and the external affairs power under section 51(xxix), used in the Tasmanian Dam Case (1983) to legislate on a state matter via a treaty.
Analysis. Judge that the statement is accurate: the federation looks similar on paper but operates far more centrally in practice. The dominant lever is finance, because the states depend on Commonwealth money. Markers reward a defended judgement supported by named cases and provisions.