Australian Army

Western Front

The AIF arrived in France with the 1st, 2nd, 4th and 5th Divisions; which comprised, in part, I ANZAC Corps and, in full, II ANZAC Corps. The 3rd Division would not arrive until November 1916, as it underwent training in England after its transfer from Australia. In July 1916, the AIF commenced operations with the Battle of the Somme, and more specifically with the Attack at Fromelles. Soon after, the 1st, 2nd and 4th Divisions became tied down in actions at the Battle of Pozières and Mouquet Farm. In around six weeks, the operations caused 28,000 Australian casualties.^[18] Due to these losses and pressure from the United Kingdom to maintain the AIF's manpower, Prime Minister Billy Hughes introduced the first conscription plebiscite. It was defeated by a narrow margin and created a bitter divide on the issue of conscription throughout the 20th century.^[19][20]

Following the German withdrawal to the Hindenburg Line in March 1917, which was better defended and eased manpower restraints, the first Australian assault on the Hindenburg Line occurred on 11 April 1917 with the First Battle of Bullecourt.^[21][22][23] On 20 September, the Australian contingent joined the Third Battle of Ypres with the Battle of Menin Road, and continued on to fight in the Battle of Polygon Wood, which lasted until 3 October; in total, these tow operations cost roughly 11,000 in Australian casualties. Until 15 November 1917, multiple attacks at the Battle of Broodseinde Ridge and the Battle of Passchendaele occurred, but, failed to take their objectives following the start of the rain and subsequent muddying of the fields.^[24]

On 21 March 1918, the Germans attempted a breakout through the Michael Offensive, which was part of the much larger German spring offensive; the AIF suffered 15,000 casualties due to this effort. During this operation, Australian troops conducted a series of local defences and offensives to hold and retake Villers–Brettoneux over the period 4 to 25 April 1918. After the cessation of offensives by the German Army, the Australian Corps began participating in "Peaceful penetration" operations, which were localised raids designed to harass and gain small tracts of territory; these proved so effective that several major operational objectives were captured.^[25]

On 4 July 1918, the Battle of Hamel saw the first successful use of tanks alongside Australians, with the battleplan of John Monash completed three minutes over the planned 90 minute operation. Following this success, the Battle of Amiens was launched on 8 August 1918, in conjunction with the Canadian Corps and the British III Corps, and concluded on 12 August 1918; General Erich Ludendorff described it as "the black day of the German Army". On 29 August 1918, following territorial advances and pursuits, the AIF attacked Pèronne and subsequently initiated the Battle of Mont St Quentin. Another operation around Épehy was planned for 18 September 1918, which aimed to retake the British trenches and, potentially, capture their most ambitious objective of the Hindenburg's outpost line – which they achieved.^[25][26][27]

Following news of a three-month furlough for certain soldiers, seven AIF battalions were disbanded; consequently, members of these battalions mutinied. Soon after the penetration of the Hindenburg Line, plans for the breakthrough of the main trench, with the Australian Corps as the vanguard, were completed. However, due to manpower issues, only the 3rd and 5th Divisions participated, with the American Expeditionary Forces' 27th and 30th Divisions given as reinforcements. On 29 September, following a three day long bombardment, the Battle of the Hindenburg Line commenced, wherein the corps attacked and captured more of the line. On 5 October 1918, after furious fighting, the Australian Corps was withdrawn from the front, as the entire corps had been operating continuously since 8 August 1918. They would not return to the battlefield, as Germany signed the Armistice of 11 November 1918 that ultimately ended the war on the Western Front.^[14][27][28]

Middle East

The Australian mounted units, composed of the ANZAC Mounted Division and eventually the Australian Mounted Division, participated in the Sinai and Palestine campaign. They were originally stationed there to protect the Suez Canal from the Turks, and following the threat of its capture passing, they started offensive operations and helped in the re-conquest of the Sinai Desert. This was followed by the Battles of Gaza, wherein on the 31 October 1917 the 4th and 12th Light Horse took Beersheba through the last charge of the Light Horse. They continued on to capture Jerusalem on 10 December 1917 and then eventually Damascus on 1 October 1918 whereby, a few days later on 10 October 1918, the Ottoman Empire surrendered.^[14][17]

Pacific

In December 1941, following the Bombing of Pearl Harbor, Australia declared war on Japan. Consequently, the AIF was requested to return home, as the subsequent rapid conquest of Southeast Asia extremely concerned Australian policymakers, and the militia was mobilised. After the Fall of Singapore, and the consequent capture of the entire 8th Division as POWs, this concern only grew. These events hastened the relief of the Rats of Tobruk, while the other divisions were immediately recalled to reinforce New Guinea.^[34] General conscription was reintroduced, though service was again limited to Australian possessions, which caused tension between the AIF and Militia. This was in addition to the CMF's perceived inferior fighting ability, with these grievances earning the Militia their nicknames of "koalas"^[a] and "chocos"^[b] or "chocolate soldiers".^{[20][41][42][43][44]}

The Imperial Japanese Navy's failure in the Battle of the Coral Sea, was the impetus for the Imperial Japanese Army to try to capture Port Moresby via the Owen Stanley Range.^[45] On 21 July 1942, the Japanese began the Kokoda Campaign after landing at Gona; attempts to defeat them by Australian battalions were met with eventual success. Resultant offensive operations concluded with the Japanese being driven out of New Guinea entirely.^[46] In parallel with these defences, the Battle of Milne Bay was waged, and when the Japanese were repulsed, it was considered their first significant reversal for the war.^[47] In November 1942, the campaign ended after the Japanese withdrawal, with Australian advances leading to the Battle of Buna–Gona.^[46][48]

In early 1943, the Salamaua–Lae campaign began, with operations against the entrenched Japanese aimed towards recapturing the eponymous towns.^[49] This culminated in the capture of Lae, held by the 7th Division in early September 1943, from a successful combined amphibious landing at Lae and an airborne landing at Nadzab. The seaborne assault was notable as it was the first large–scale amphibious operation since Gallipoli. Subsequently, Salamaua was taken days later on 11 September 1943, by a separate joint Australia–US attack.^[50][51] The Battle of Lae was additionally part of the wider Huon Peninsula campaign. Following Lae's capture, the Battle of Finschhafen commenced with a relatively swift control of objectives, with subsequent Japanese counterattacks beaten off. On 17 November 1943, a major offensive that began with the Battle of Sattelberg, continued with the Battle of Wareo, and concluded with the Battle of Sio on 15 January 1944, was unleashed. The momentum of this advance was continued by the 8th Brigade, as they pursued the enemy in retreat, which culminated with the Battle of Madang.^[51][52]

In mid-1944, Australian forces took over the garrisoning of Torokina from the US with this changeover giving Australian command responsibility over the Bougainville campaign. Soon after arriving in November of the same year, the commander of II Corps, Lieutenant-General Stanley Savige, began an offensive to retake the island with the 3rd Division alongside the 11th and 23rd Brigades. The campaign lasted until the Japanese surrender, with controversy surrounding its little apparent significance to the war's conclusion, and the number of casualties incurred; this was one of Australia's most costliest campaigns in the Second World War.^[53]

In October 1944, Australian participation in the Aitape–Wewak campaign began with the replacement of US forces at Aitape with the Australian 6th Division. US forces had previously captured the position, and had held it passively, though Australian command found this unsuitable. On 2 November 1944, the 2/6th Cavalry Commando Regiment was tasked with patrolling the area, wherein minor engagements were reported. In early December, the commandos were sent inland to establish access to the Torricelli Range, while the 19th Brigade handled patrolling, consequently, the amount of fierce fighting and territory secured increased. Following this success, thought was given for the capture of Maprik and Wewak, though supply became a major issue in this period. On 10 February 1945, the campaign's major offensive was underway, which resulted in both falling in quick succession on 22 April 1945. Smaller operations to secure the area continued, and all significant actions ceased by July.^[54][55]

The Borneo campaign was a series of three distinct amphibious operations that were undertaken by the 7th and 9th Divisions. The campaign began with the Battle of Tarakan on 1 May 1945, followed six weeks later by the Battle of Labuan, and concluded with the Battle of Balikpapan. The purpose of capturing Tarakan was to establish airfields, and the island was taken seven weeks following the initial amphibious landing. On 10 June 1945, the operation at Labuan commenced, and was tasked to secure resources and a naval base, and would continue until Japan's surrender. On 1 July 1945, the Balikpapan engagement commenced, with all its major objectives being acquired by war's end; this operation remains the largest amphibious operation undertaken by Australian forces, with 33,000 Australian servicemen participating. On 15 August 1945, Japan surrendered, ending the Second World War.^[56][57][58]

Korean War

After the surrender of Japan, Australia provided a contingent to the British Commonwealth Occupation Force (BCOF) which included the 34th Brigade. The units that composed the brigade would eventually become the nucleus of the regular army, with the battalions and brigade being renumbered to reflect this change. Following the start of the Korean War, the Australian Army committed troops to fight against the North Korean forces; the units came from the Australian contribution to BCOF. The 3rd Battalion, Royal Australian Regiment (3RAR) arrived in Pusan on 28 September 1950. Australian troop numbers would increase and continue to be deployed up until the armistice, with 3RAR being eventually joined by the 1st Battalion, Royal Australian Regiment (1RAR).^[59][60] For a brief period, between 1951 and 1959, the Menzies Government reinstituted conscription and compulsory military training with the National Service Scheme, which required all males of eighteen years of age to serve for specified period in either the Australian Regular Army (ARA) or CMF.^[43][61]

Malayan Emergency

The Australian military entered the Malayan Emergency (1948–1960) in October 1955, committing the 2nd Battalion, Royal Australian Regiment (2RAR) to fight alongside Commonwealth forces. The 2RAR fought against the Malayan National Liberation Army (MNLA), a communist led guerrilla army whose goal was to turn Malaya into a socialist republic, and whose leaders had previously been trained and funded by Britain to resist the Japanese occupation of Malaya. Australian military operations in Malaya consisted of patrolling actions and guarding infrastructure, though they rarely saw combat as the emergency was nearly over by the time of their deployment. All three original Royal Australian Regiment battalions would complete at least one tour before the end of operations. In August 1963, Australia ended deployments to Malaya, three years after the emergency's official end.^[62]

Indonesia–Malaysia confrontation

In 1962, the Borneo Confrontation began, due to Indonesia's opposition to the formation of Malaysia. It was an undeclared war that entailed a series of border conflicts between Indonesian-backed forces and British–Malaysian allies. Initial Australian support in the conflict began, and continued throughout, with the training and supply of Malaysian troops; Australian soldiers only saw combat during defensive operations. In January 1965, permission was granted for the deployment of 3RAR, with extensive operations conducted in Sarawak from March until their withdrawal in July 1965. The subsequent deployment of 4th Battalion, Royal Australian Regiment (4RAR), in April 1966, was less intensive, with the battalion withdrawn in August. This is not to mention the efforts of several other corps and units in the conflict.^[63][64]

Vietnam War

The Australian Army commenced its involvement in the Vietnam War by sending military advisors in 1962, which was then increased by sending in combat troops, specifically 1RAR, on 27 May 1965. Just before the official start of hostilities, the Australian Army was augmented with the reintroduction of conscription, which was based on a 'birthday ballot' selection process for all registered 20-year-old males. These men were required to register, unless they gave a legitimate reason for their exemption, else they faced penalties. This scheme would prove to be one of the most controversial implementations of conscription in Australia, with large protests against its adoption.^{[65][66][43][61]}

In March 1966, the Australian Army increased its commitment again with the replacement of 1RAR with the 1st Australian Task Force, a force in which all nine battalions of the Royal Australian Regiment would serve. One of the heaviest actions of the war occurred in August 1966, with the Battle of Long Tan, wherein D Company, 6th Battalion, Royal Australian Regiment (6RAR) successfully fended off an enemy force, estimated at 2,000 men, for four hours. In 1968, Australian forces defended against the Tet Offensive, a Viet Cong military operation, and repulsed them with few casualties. The contribution of personnel to the war was gradually wound down, starting in late-1970 and ending in 1972; the official declaration of the end of Australia's involvement in the war was made on 11 January 1973.^[65][66]

Activities in Africa

Following the Vietnam War, there was a significant hiatus of operational activity by the Australian Army. In late 1979, in the largest deployment of the decade, the Army committed 151 troops to the Commonwealth Monitoring Force, which monitored the transition of Rhodesia to universal suffrage. A decade later in 1989, Australia deployed 300 army engineer personnel as the Australian contribution to the United Nations Transition Assistance Group in Namibia. The mission helped transition the country to independence from South African control.^[67]

Peacekeeping

Following the invasion of Kuwait by Iraq in August 1990, a coalition of countries sponsored by the United Nations Security Council, of which Australia was a part, gave a deadline for Iraq to withdraw from Kuwait of the 15 January 1991. Iraq refused to retreat and thus full conflict and the Gulf War began two days later on 17 January 1991.^[68] In January 1993, the Australian Army deployed 26 personnel on an ongoing rotational basis to the Multinational Force and Observers (MFO), as part of a non-United Nations peacekeeping organisation that observes and enforces the peace treaty between Israel and Egypt.^[69]

Australia's largest peacekeeping deployment began in 1999 with the International Force for East Timor, while other ongoing operations include peacekeeping in the Sinai (as part of MFO), and the United Nations Truce Supervision Organization (as part of Operation Paladin since 1956).^[70] Humanitarian relief after the 2004 Indian Ocean earthquake in Aceh Province, Indonesia, Operation Sumatra Assist, ended on 24 March 2005.^[71]

Afghanistan and Iraq

Following the 11 September 2001 terrorist attacks, Australia promised troops to any military operations that the US commenced in response to the attacks. Subsequently, the Australian Army committed combat troops to Afghanistan in Operation Slipper. This combat role continued until the end of 2013 when it was replaced by a training contingent operating under Operation Highroad until 2021.^[72][73]

After the Gulf War the UN imposed heavy restrictions on Iraq to stop them producing any Weapon of mass destruction. In the early 21st century, the US accused Iraq of possessing these weapons, and requested that the UN invade the country in response, a motion which Australia supported. The UN denied this motion, however, it did not stop a coalition, that Australia joined, invading the country; thus starting the Iraq War on 19 March 2003.^[74]

Between April 2015 and June 2020, the Army deployed a 300-strong element to Iraq, designated as Task Group Taji, as part of Operation Okra. In support of a capacity building mission, Task Group Taji's main role was to provide training to Iraqi forces, during which Australian troops have served alongside counterparts from New Zealand.^[75][76]

In 2020 an investigation of allegations of war crimes committed during Australian military operations in Afghanistan was concluded with the release of the Brereton Report. The report identified 25 ADF personnel that were involved directly or indirectly in the murder of 39 civilians and prisoners, with 19 referred to the Australian Federal Police to be criminally investigated. A 'warrior culture' in the SAS was specifically criticised with investigators 'frustrated by outright deceit by those who knew the truth and, not infrequently, misguided resistance to inquiries and investigations by their superiors'.^[77]