Section 51(vi) of the Constitution of Australia

Section 51(vi) of the Australian Constitution, commonly called the defence power, is a subsection of Section 51 of the Australian Constitution that gives the Commonwealth Parliament the right to legislate with respect to "the naval and military defence of the Commonwealth and of the several States, and the control of the forces to execute and maintain the laws of the Commonwealth".

Section 51(vi) and the Australian States

Generally, powers in section 51 of the Australian Constitution can also be legislated on by the states, although Commonwealth law will prevail in cases of inconsistency. However, the defence power must be read in conjunction with other parts of the Australian Constitution — namely,

114. A State shall not, without the consent of the Parliament of the Commonwealth, raise or maintain any naval or military force, or impose any tax on property of any kind belonging to the Commonwealth, nor shall the Commonwealth impose any tax on property of any kind belonging to a State.

and

119. The Commonwealth shall protect every State against invasion and, on the application of the Executive Government of the State, against domestic violence.

This effectively makes the defence power exclusive to the Commonwealth.

Breadth of Section 51(vi)

See also: Category:Defence power in the Australian Constitution cases

The defence power allows the Commonwealth to raise an army and navy. Although air forces did not exist in 1901, "military defence" has been considered broad enough to include an air force. What other laws the defence power will support has been held by the High Court of Australia to vary based on external circumstances.

During the two World Wars, the power was held to apply very broadly, even to domestic issues. In the First World War, the War Precautions Act 1914 allowed for the making of regulations over a wide range of fields, including price controls, the last of which was upheld by the High Court as a valid exercise of the defence power. As Isaacs J. (as he then was) observed in Farey v Burvett:

I do not hold that the Legislature is at liberty wantonly and with manifest caprice to enter upon the domain ordinarily reserved to the States. In a certain sense and to a certain extent the position is examinable by a Court. If there were no war, and no sign of war, the position would be entirely different. But when we see before us a mighty and unexampled struggle in which we as a people, as an indivisible people, are not spectators but actors, when we, as a judicial tribunal, can see beyond controversy that co-ordinated effort in every department of our life may be needed to ensure success and maintain our freedom, the Court has then reached the limit of its jurisdiction. If the measure questioned may conceivably in such circumstances even incidentally aid the effectuation of the power of defence, the Court must hold its hand and leave the rest to the judgment and wisdom and discretion of the Parliament and the Executive it controls—for they alone have the information, the knowledge and the experience and also, by the Constitution, the authority to judge of the situation and lead the nation to the desired end.

Accordingly, the defence power has been held to include:

• the preparation for war and against war, whether internal or external, and whether actually performed or only apprehended
• the punishment, and prevention, of injurious activities, including espionage and fifth column work
• the creation of measures for combatting terrorism
• being used to compel the transfer of civil servants and facilities involved in the collection of income taxes from the States to the Commonwealth
• taking possession of and controlling property, confiscating literature, and prohibiting public meetings of organizations whose activities are prejudicial to the defence of the Commonwealth or the prosecution of the war

However:

• organizations cannot be deemed to be unlawful under an Act, and
• such organizations cannot themselves be dissolved as a result

There have been attempts to employ a broad interpretation to the defence power. In 1949 the Commonwealth used it to support the introduction of the Snowy Mountains Hydroelectricity Scheme, as, although wartime hostilities had ceased, a secure electricity source was needed should Australia be attacked. The constitutionality of this was never tested, and the point became moot ten years later in 1959, when corresponding State legislation was passed to support it.

Notable cases

• Farey v Burvett [1916] HCA 36, (1916) 21 CLR 433 (8 June 1916), High Court
• Adelaide Company of Jehovah's Witnesses Incorporated v Commonwealth [1943] HCA 12, (1943) 67 CLR 116 (14 June 1943), High Court
• Australian Communist Party v Commonwealth ("Communist Party case") [1951] HCA 5, (1951) 83 CLR 1 (9 March 1951), High Court
• Thomas v Mowbray [2007] HCA 33 (2 August 2007), High Court