First World War

The outbreak of war in Europe in August 1914 automatically involved "all of Britain's colonies and dominions".[237] Prime Minister Andrew Fisher probably expressed the views of most Australians when during the election campaign of late July he said:

“ Turn your eyes to the European situation, and give the kindest feelings towards the mother country.... I sincerely hope that international arbitration will avail before Europe is convulsed in the greatest war of all time.... But should the worst happen... Australians will stand beside our own to help and defend her to the last man and the last shilling.[237] ”

More than 416,000 Australian men volunteered to fight during the First World War between 1914 and 1918[238] from a total national population of 4.9 million.[239] Historian Lloyd Robson estimates this as between one third and one half of the eligible male population.[240] The Sydney Morning Herald referred to the outbreak of war as Australia's "Baptism of Fire."[241] 8,141 men[242] were killed in 8 months of fighting at Gallipoli, on the Turkish coast. After the Australian Imperial Forces (AIF) was withdrawn in late 1915, and enlarged to five divisions, most were moved to France to serve under British command.

Some forces remained in the Mid-East, including members of the Light Horse Regiment. Light horseman of the 4th and 12th Regiments captured heavily fortified Beersheba from Turk forces by means of a cavalry charge at full gallop on 31 October 1917. One of the last great cavalry charges in history, the attack opened a way for the allies to outflank the Gaza-Beersheba Line and drive the Ottomans back into Palestine.[243]

The AIF's first experience of warfare on the Western Front was also the most costly single encounter in Australian military history. In July 1916, at Fromelles, in a diversionary attack during the Battle of the Somme, the AIF suffered 5,533 killed or wounded in 24 hours.[244] Sixteen months later, the five Australian divisions became the Australian Corps, first under the command of General Birdwood, and later the Australian General Sir John Monash. Two bitterly fought and divisive conscription referendums were held in Australia in 1916 and 1917. Both failed, and Australia's army remained a volunteer force.

 
General Sir John Monash in 1918.John Monash was appointed corps commander of the Australian forces in May 1918 and led some significant attacks in the final stages of the war. British Field Marshal Montgomery later called him "the best general on the western front in Europe". Monash made the protection of infantry a priority and sought to fully integrate all the new technologies of warfare in both the planning and execution of battles, thus he wrote that infantry should not be sacrificed needlessly to enemy bayonets and machine guns—but rather should "advance under the maximum possible protection of the maximum possible array of mechanical resources, in the form of guns, machine-guns, tanks, mortars and aeroplanes". His first operation at the relatively small Battle of Hamel demonstrated the validity of his approach and later actions before the Hindenburg Line in 1918 confirmed it. Monash was knighted in the field of battle by King George V following 8 August advance during the Battle of Amiens.[245] General Erich Ludendorff, the German commander, later wrote of 8 August 1918 as "the black day of the German Army... The 8th of August put the decline of [German] fighting power beyond all doubt".[246] Amiens, fought between 8 and 11 August 1918, marked the beginning of the allied advance that culminated in the 11 November Armistice ended the war.[246]

Over 60,000 Australians had died during the conflict and 160,000 were wounded, a high proportion of the 330,000 who had fought overseas.[238]

While the Gallipoli campaign was a total failure militarily and 8100 Australians died, its memory was all-important. Gallipoli transformed the Australian mind and became an iconic element of the Australian identity and the founding moment of nationhood.[247] Australia's annual holiday to remember its war dead is held on ANZAC Day, 25 April, each year, the date of the first landings at Gallipoli in 1915.[248] The choice of date is often mystifying to non-Australians; it was after all, an allied invasion that ended in military defeat. Bill Gammage has suggested that the choice of 25 April has always meant much to Australians because at Gallipoli, "the great machines of modern war were few enough to allow ordinary citizens to show what they could do." In France, between 1916 and 1918, "where almost seven times as many (Australians) died,... the guns showed cruelly, how little individuals mattered."[249]

In 1919, Prime Minister Billy Hughes and former Prime Minister Joseph Cook took Australia's seat at the Versailles peace conference.[250] Hughes' signing of the Treaty of Versailles was the first time Australia had signed an international treaty. Hughes demanded heavy reparations from Germany and frequently clashed with US President Woodrow Wilson. At one point Hughes declared: "I speak for 60,000 [Australian] dead".[251] He went on to ask of Wilson; "How many do you speak for?"

Hughes demanded that Australia have independent representation within the newly formed League of Nations and was the most prominent opponent of the inclusion of the Japanese racial equality proposal, which as a result of lobbying by him and others was not included in the final Treaty, deeply offending Japan. Hughes was concerned by the rise of Japan. Within months of the declaration of the European War in 1914; Japan, Australia and New Zealand seized all German possessions in the South West Pacific. Though Japan occupied German possessions with the blessings of the British, Hughes was alarmed by this policy.[252] In 1919 at the Peace Conference the Dominion leaders argued their case to keep their occupied German possessions and these territories were given a "Class C Mandates" to the respective Dominions. Japan obtained control over the South Pacific Mandate, north of the equator.[252] German New Guinea, the Bismarck Archipelago and Nauru were assigned to Australia as League of Nations Mandates: in the category of territories "formerly governed [by the Central Powers] and which are inhabited by peoples not yet able to stand by themselves under the strenuous conditions of the modern world".[253] Thus the Territory of New Guinea came under Australian administration