In no case since WW2 has ‘war’ been actually declared by Australia. Rather it was by and large a process into which the country drifted, from low-level engagements into larger conflicts.
World War I
Australia was committed because Britain was at war; the Empire was one and indivisible. Notwithstanding, in clear shows of voter opinion, two referenda on conscription were rejected.
World War II
Because Britain had declared war, Australia was at war too (notwithstanding the Statute of Westminster, not then adopted).
UN Security Council authorised. Australia’s ‘forward defence’ doctrine made commitment with the US effectively, according to the political consensus in Canberra and in the press, obligatory. It was a time of global tension, with the ANZUS treaty in prospect. Note: formal ‘state of war’ not yet terminated in Korea; a formal Armistice has been in force since 1953.
The Malayan Emergency (1950s)
A security operation in support of a British colony. Communist insurgency, as alleged by the British, was seen as a direct threat to regional stability. Another instance of ‘forward defence’ in action. Elements of the armed forces were already based in the area. Parliamentary authorisation implied ex post facto through financial appropriations.
Decision was taken by Cabinet over several months (late 1964 – April 1965), through Foreign Affairs & Defence Committee processes, but without Defence Committee advice. The final decision was taken in Cabinet. Parliamentary authorisation was implied ex post facto through financial appropriations. This was a war marked, and marred, by the Draft (i.e. conscription).
Indonesia (‘Konfrontasi’, 1963-66)
Australian troops were engaged secretly from time to time in irregular scouting operations over the Indonesian (Borneo) border to deal with local guerrilla activity. Authorised by Cabinet but not referred to Parliament. Costs were borne from Defence Department appropriations.
Iraq War No 1 (1990-91)
A UN sanctioned operation, responding to an act of international aggression and a ‘threat to the peace’ in UN Charter terms. Parliamentary authorisation was not sought but implied ex post facto through financial appropriations. The decision to act was taken by the Prime Minister, but not without controversy in Cabinet. A Governor-General-in-Council process occurred eventually.
A UN sanctioned operation. It appears the Governor-General in Council was not directly engaged in the process. Parliamentary authorisation was not sought but could be implied ex post facto through financial appropriations. While its purpose changed over time, that was never formally debated or put to Parliament. The open-ended nature of the operation caused considerable public concern.
Iraq War No 2 (2003)
The decision to support the United States with armed forces was taken by the Prime Minister whilst overseas (in US), possibly following telephone consultation with Foreign Minister, in the face of substantial domestic political opposition and disquiet. The invasion began on 18th March before the ultimatum to Saddam Hussain had expired. The Governor-General in Council process was not directly engaged. (Indeed the G-G was not even consulted). Parliamentary authorisation was not sought but could be inferred expost facto and indirectly through financial appropriations. Not UN sanctioned.
Armed action in this case was said to be illegal under international law.
Iraq War No 3 (2014)
Deployment of RAAF squadron in UAE for bombing operations in northern Iraq against ‘Islamic State’ (ISIL) terrorist forces. Special SAS forces were deployed in the area to provide “training” (combat support and direction) for Iraqi forces. Operations were approved by Cabinet on advice of the National Defence & Security Committee of Cabinet. No Parliamentary involvement.
A UN sanctioned peacekeeping operation, largely led by Australia, with indifferent results.
The Solomon Islands
Police and security operation (RAMSI), essentially peacekeeping in nature with regional support.
East Timor operation (INTERFET)
Peacekeeping and security in character, to facilitate the independence plebiscite and secure stability thereafter. It was consented to by all concerned parties, including Indonesia, and with UN and other international sanction.
Ukraine (July-August 2014)
Following the as yet unexplained downing of Malaysian Airlines MH17, with the loss of Australian and other lives, the Prime Minister proposed the deployment of “unarmed” federal police, plus (armed) Defence Forces personnel to assist the investigation and to obtain justice for the victims and families. The proposed deployment did not proceed and was not considered by Parliament.
• Note also Parliamentary Library paper on war powers at: