Aid to the civil power

Military aid to the civil power (MACP) (sometimes to the civil authorities) is a term used to describe the use of the armed forces in support of the civil authorities of a state. The term is used in many countries, with slightly different definitions and implications in each.

Under certain circumstances, the Australian Defence Force can be called upon assist with law enforcement. State or Territory civilian police have primary responsibility for law and order. Under section 119 of the Constitution of Australia, "The Commonwealth shall protect every State against invasion and, on the application of the Executive Government of the State, against domestic violence." This is further explained in section 51 of the Defence Act which states that:

Where the Governor of a State has proclaimed that domestic violence exists therein, the Governor-General, upon the application of the Executive Government of the State, may, by proclamation, declare that domestic violence exists in that State, and may call out the Permanent Forces and in the event of their numbers being insufficient may also call out such of the Emergency Forces and the Reserve Forces as may be necessary for the protection of that State, and the services of the Forces so called out may be utilised accordingly for the protection of that State against domestic violence.

Military forces have been deployed twice on the request of State or Territory governments, and deployment authorised on one other occasion but not required:

Australian Military Regulations also allow the Federal government to use military forces "on its own initiative, for the protection of its servants or property, or the safeguarding of its interests". This has been done three times:

In addition, unarmed troops and defence force equipment have been used in industrial disputes, such as the 1949 Australian coal strike and the 1989 Australian pilots' dispute, under the "safeguarding of its interests" provisions.

Canada has provisions, similar to the UK's Military Aid to the Civil Authorities, for military aid to the civil power inscribed in its National Defence Act, an historical inheritance from its days as a British dominion. However, the application is significantly different due to the federal nature of Canada, where the maintenance of "law and order" is the exclusive right and responsibility of the provinces.

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