Britain declares war on Russia, beginning British involvement in the Crimean War. The news leads to the establishment of a volunteer corps in some colonies, and the formation of rifle clubs in others. The units are revived in 1859 as Napoleon III prepares to invade England. By early 1860 most suburbs and towns in Australia support a volunteer unit, usually a rifle corps.

A volunteer NSW infantry contingent fights for Britain in the Sudan. This is the first time that soldiers representing an Australian colony engage in an imperial war.

The first Colonial Conference, held in London, involves representatives from all British colonies meeting to discuss common concerns. The Australian colonies present a united front on French activity in the New Hebrides and Britain agrees to maintain a presence.

As part of the British Empire, the Australian colonies offer to send troops to the war in South Africa against the Boers or Afrikaners, settlers of Dutch descent seeking to create a republic in the Transvaal. At least 12,000 Australians serve in contingents raised by the six colonies and, from 1901 by the new Australian Commonwealth. Many more join British or South African colonial units in South Africa. At least 600 Australians die in the war, about half from disease and half in action.

Liang Qichao, the most important democrat in Chinese history and a leading journalist and political observer, tours Australia at the invitation of the Protect the Emperor Society established by the Chinese in Sydney. Liang advocates reform of China’s political system and economy along western lines, and his visit arouses considerable interest in Australia. Arriving at the conclusion of the Boxer Uprising in northern China, Liang is seen as a potential national leader for a modernised China.

The Commonwealth’s Constitutional powers include the power to legislate for national defence. The new Commonwealth government takes control of the former colonial military forces and creates a small regular army and Citizen Military Forces comprised of reservists who cannot be deployed overseas. The first Australian Imperial Force (AIF) is formed in 1914 as the main expeditionary force of the Australian Army during World War I, and the Second Australian Imperial Force (2nd AIF) is formed in 1939 from volunteer units of the Australian Army to fight in World War II. The modern Australian Army is formed in 1947.

The Defence Act 1903 is passed, providing for a national military force within Australia. All men aged 18 to 60 years are obliged to serve in war unless exempted on religious grounds. Only volunteers can serve overseas. Billy Hughes is a key proponent of compulsory military training but Justice HB Higgins presses for conscientious objection and the Act becomes the first national legislation to grant exemption from military service on the grounds of conscientious belief.

Rose Scott, a leading suffragist, writes to Prime Minister Alfred Deakin opposing compulsory military training and service. In 1914, Vida Goldstein forms the Women’s Political Alliance to oppose military conscription, then joins Cecilia Annie John forming the Women’s Peace Army.

The visit of the Great White Fleet of 16 US warships represents a spectacular show of naval strength and alliance. Invited by Prime Minister Alfred Deakin, against the wishes of the British Government, the fleet is welcomed to Australia with a week of celebrations and a public holiday.

The Defence Act 1909 introduces compulsory military training of males during peacetime. Aboriginal men are excluded. The Act is amended in 1910 to provide for conscientious objection to the bearing of arms, but this exemption does not apply to the universal compulsory military training between 1911 and 1929 for males aged 12 to 26 years. Objectors faced fines and gaol.

The Australian High Commission opens in London with a former prime minister, George Reid, as the first High Commissioner.

Duntroon Royal Military College is established in Canberra to train professional officers for military duty.

Britain, France and Russia (the Triple Entente) fight against Germany, Turkey and the Austro-Hungarian Empire. The United States enters in 1917 on the side of Britain. On 26 April 1915 Italy comes into the war on the side of the Triple Entente. Japan is also allied with the Triple Entente, securing sea lanes in the Pacific and Indian oceans against the Kaiser’s navy. World War I ends with an armistice on 11 November 1918. In 1919, Austria and Germany become republics. The Treaty of Versailles imposes reparations to be paid to the Allies, limits the German armed forces and prohibits their development, and enforces territorial losses against Germany. The Treaty also establishes new international bodies such as the League of Nations and the International Labour Organization.

On 25 April 1915 members of the Australian Imperial Force land at Gallipoli, together with troops from New Zealand, Britain and France. The landing signals the start of one of Australia’s most commemorated military campaigns, ends with the evacuation of the remaining troops after eight months of battle. Following Gallipoli, Australian servicemen fight with Allied forces in campaigns on the Western Front and in the Middle East.

At the end of the Gallipoli campaign in 1915, the Australian Imperial Force begins to move to France. All five divisions see much action on the Western Front and, as the enormity of Australian casualties become known in Australia, the number of men volunteering for service falls steadily. The federal government comes under sustained pressure from Britain to ensure that its divisions are not depleted. In 1916 it is argued that Australia needs to provide reinforcements of 5500 men per month to maintain its forces overseas at operational level. Prime Minister Hughes decides to ask the people in a referendum if they would agree to a proposal requiring men undergoing compulsory training to serve overseas. The referendum, held on 28 October 1916, is defeated with 1,087,557 in favour and 1,160,033 against.

The government introduces compulsory registration of ‘aliens’ during in World War I with the War Precautions (Alien Registration) Regulations 1916, forcing ‘aliens’ to register with customs officials or the local police. The government subsequently introduces an internment policy, requiring those born in countries at war with Australia and classed as ‘enemy aliens’ to be relocated to camps. This is expanded to include people from enemy nations who are naturalised British subjects, Australian-born descendants of migrants from enemy nations and others who are thought to pose a threat to Australia’s security. Australia interns almost 7000 people during World War I, of whom about 4500 are enemy aliens and British nationals of German ancestry already resident in Australia.

As the Australian public learns of the enormity of Australian casualties on the Western Front, the number of men volunteering for service falls and Prime Minister W M Hughes puts the question of military conscription to the public. Australians are divided over the issue of compulsory conscription for overseas service, with conservative political parties, the media and most church leaders supporting conscription, while trade unions and many women’s groups oppose it. The referendum of 28 October asks ‘Are you in favour of the Government having, in this grave emergency, the same compulsory powers over citizens in regard to requiring their military service, for the term of this War, outside the Commonwealth, as it now has in regard to military service within the Commonwealth?’. The referendum is defeated with 1,087,557 in favour and 1,160,033 against. A second referendum in 1917 also fails and the issue divides the nation politically, socially and along religious lines.

The armistice to end World War I is signed on 11 November, and the Treaty of Versailles is concluded in June 1919. The Treaty of Versailles creates the Covenant of the League of Nations, and is signed by Prime Minister William Hughes and Minister for the Navy, Joseph Cook. This is the first political treaty signed by Australian officials, and the first negotiated with direct participation by Australian Government delegates after Hughes insisted on Australia’s right to attend the Peace Conference in its own right rather than be represented by Britain. He also persuades leaders from New Zealand, South Africa, Canada and the United Kingdom to oppose Japan’s bid for a racial equality clause to be inserted in the Covenant of the League of Nations.

Australia is among 32 signatories of the Treaty of Versailles, and a founding member of the League of Nations established by the Treaty. The League is officially inaugurated on 10 January 1920, when the Treaty of Versailles comes into force.

As tensions rise over Japan’s invasion of Manchuria, Port Kembla waterside workers refuse to load a cargo of pig-iron destined for Japanese munitions factories. The Commonwealth government intervenes to contest the right of a trade union to determine national foreign policy. The Attorney-General, Robert Menzies, earns the nickname ‘Pig-Iron Bob’ for his role in the dispute.

Australia’s first diplomatic posts are set up in Washington, DC, Tokyo and Ottawa.

In November, Prime Minister John Curtin argues at a special Federal Conference of the Labor Party that it is necessary for the war effort to extend government powers to compel service in the south-west Pacific comprising Australia, New Guinea, the Philippines and the Netherlands East Indies. During World War I, Curtin had argued passionately against compulsory enrolment for overseas military service. Amidst bitter debate within the Labor Party, the War Cabinet approves a Bill to empower the Australian Government to send conscripts out of Australian territory to a defined south-west Pacific war zone. The Bill becomes the Defence (Citizen Military Forces) Act 1943 (Cth). It obliges soldiers in the Citizen Military Forces to serve in Australia, all of the island of New Guinea and the adjacent islands. This is called the South-West Pacific Zone.

In an extraordinary exchange of cablegrams, Prime Minister John Curtin defies British Prime Minister Winston Churchill and US President Franklin Roosevelt and orders Australia’s 7th Division home rather than to Burma. In March, Rangoon falls to Japanese forces and Allied troops are interned as prisoners of war, with many forced to work on the notorious Burma railway.

The outbreak of war with Japan on 8 December 1941 provokes panic amongst the Australian public. When Singapore falls to Japanese forces on 15 February 1942, the Prime Minister John Curtin announces that this is the start of the ‘Battle for Australia’ and military chiefs of staff recommend all Australia’s forces be redeployed from the Middle East to Australia. On 19 February 1942 Japanese forces conduct air raids on Darwin. This is the first direct attack on Australia by an external enemy since British colonisation. Two weeks later, on 3 March, Japanese fighters hit Broome killing 70 people and destroying 24 aircraft. Air raids are also conducted on Wyndham, Derby, Horn Island, and Townsville, ships are sunk of Australia’s east coast, and submarine attacks are made on Newcastle and Sydney.

By the end of World War II, 540,000 Australians have enlisted compared with 417,000 in World War I, but fewer die in action — 33,826, compared with nearly 60,000.

Lasting 13 years, the Malayan Emergency was the longest continuous military commitment in Australia’s history. The Emergency is declared on 18 June 1948, after three estate managers are murdered in northern Malaya by guerrillas of the Malayan Communist Party, an outgrowth of the anti-Japanese guerrilla movement that had emerged during World War II. Australian forces form part of the Far East Strategic Reserve established in 1955 to deter external communist aggression in South-East Asia. Thirty-nine Australian servicemen are killed in Malaya.

The Australian Nationality and Citizenship Act 1948, proclaimed on 26 January 1949, recognises that Australians are now citizens of their own country as well as British subjects. Unlike previous laws, the new Act implicitly includes Aboriginal people by including the category ‘natural-born’. It still refers to non-British subjects as ‘aliens’ (except Irish citizens and ‘protected persons’). The concept of ‘British subject’ is removed in 1973.

The Chifley government establishes the Australian Security Intelligence Organization (ASIO) to provide the federal government with security intelligence about activities that might harm Australia. It is formed at a time of increasing anxiety over Soviet espionage activities, sparked by the defection in Canada of Igor Gouzenko in 1946. ASIO is subject to two royal commissions in 1974–77 and 1983–84, which focus on the organisation’s accountability and the tension between maintaining civil liberties while protecting Australia’s national security.

Following revelations after World War II of sensitive British and Australian Government data being transmitted through Soviet diplomatic channels and the subsequent discovery of a spy ring operating from the Soviet Embassy in Canberra, allied western governments express dissatisfaction with the state of security in Australia. On 16 March, Prime Minister Ben Chifley issues a Directive for the Establishment and Maintenance of a Security Service, appointing South Australian Supreme Court Justice Geoffrey Reed as the first Director-General of Security. In August, Justice Reed advises the Prime Minister that he has decided to name the service the Australian Security Intelligence Organization (ASIO). The new service is modelled on the Security Service of the United Kingdom and an MI5 liaison team is attached to the fledgling ASIO during the early 1950s.

Towards the end of World War II, US and Soviet forces occupy the Korean peninsula, having liberated it from Japan. The two powers divide responsibility for Korea between themselves at the 38th parallel. A Soviet-supported communist regime emerges in the north and a US-backed one in the south. Both regimes seek reunification — but under their respective governments. On 25 June, the North Korean army pushes south. The United States sends in support to the south and the United Nations enlists 21 nations against the north. When the UN force enters the north, the Chinese move in with several army divisions. More than 1.5 million people die in various battles. A peace agreement is reached on 27 July 1953.

The first students arrive in Australia under the Colombo Plan, a scheme established by Commonwealth nations to provide aid to improve economic and social conditions in developing countries in South and South-East Asia. The Plan is considered an important means of improving stability in the region, and thereby enhancing Australia’s national security.

Australia, New Zealand and the United States sign a defence security pact for the Pacific area. It offers Australia and New Zealand protection against a possible threat of Soviet or Chinese aggression and the United States gains support against communism in the Pacific region.

Australia, France, New Zealand, Pakistan, the Philippines, Thailand, the United Kingdom and the United states sign the Southeast Asia Collective Defense Treaty (SEATO) at Manila. The Treaty is a response to the spread of communism in Southeast Asia, and it strengthens Australian military ties with the United States. It is dissolved in 1977.

Prime Minister Robert Menzies announces to parliament the defection of Soviet Embassy official Vladimir Petrov and his wife Evdokia, on the eve of the 1954 federal election. The defection, together with the subsequent Royal Commission into Espionage, become known as the Petrov Affair. It adds to existing tensions within the Labor Party over the issue of communism, tensions that ultimately result in a split in the Party and the formation of the anti-communist Democratic Labor Party.

The Menzies government introduces a compulsory military training scheme for Australian men born on dates chosen in a ballot system, dubbed ‘a lottery of death’ by Labor opposition leader Arthur Calwell. The National Service Act 1964 enables the federal government to conscript men for a two-year term and for a further three years in the Army Reserve, with exemptions granted on fitness and educational grounds. The first conscripts are sent to Vietnam and Malaya in 1965, and two ballots are held each year until 1972. Those opposed to war, or to service in Vietnam, mount a bitter and prolonged anti-conscription campaign that divides public opinion. The National Service scheme is wound up in 1973 with the passing of the National Service Termination Act by the Whitlam government.

On 29 April 1965 Prime Minister Robert Menzies announces to a nearly empty House of Representatives that Australia will increase its commitment to the growing war in Vietnam with the addition of a battalion of ground troops, in addition to the advisers already in the country. The commitment is well received by the public, although opposition begins to grow once the first national servicemen are included for Vietnam service in 1965.

Between 1965 and 1968 Australia’s military commitment in Vietnam grows to three army battalions, navy and air force contingents, and an extensive support network. By the time most Australian troops are withdrawn at the end of 1972, nearly 60,000 soldiers, sailors and airmen have served. Of those, 521 are killed (including 200 national servicemen), and over 3000 wounded. The war divides Australian society and creates some of the largest anti-war protests the country has ever seen.

In the aftermath of the war, Australian veterans deal with health and psychological problems that last for several decades, with many fighting a battle for compensation due to possible exposure to herbicides in Vietnam.

In Vietnam, approximately two million soldiers and civilians from both the North and South are killed, before the south falls to the communist north on 30 April 1975 and the conflict ends.

The Save Our Sons group forms in protest against the sending of national servicemen to the Vietnam War. Initially established in Sydney, the movement gains supporters across Australia and comprises mostly non-working women whose sons are old enough to be called up for National Service. The protesters, while generally limited to vigils and circulating petitions and pamphlets, are called communists and criticised as neglectful mothers and wives. Over 10 years, however, they emerge as effective critics of conscription, and many women find their own political voice for the first time.

During the first Vietnam Moratorium, thousands of Australians gather in all state capitals and country towns and cities to protest against Australia’s ongoing involvement in the Vietnam War. The issue had divided the country since the commitment of combat troops in 1965, with many people objecting to conscripts being sent to fight. Two further Moratorium marches take place in 1970 and 1971, and they are some of the largest protests the country has ever seen. The protests begin to diminish once Australia starts to withdraw its troops from Vietnam from 1970 onwards, and by the end of 1972 the war is no longer a major issue.

Following a high-profile and sometimes violent public campaign against Australia’s involvement in the Vietnam War, the last Australian troops are brought home by a proclamation by the Governor-General, officially ending Australia’s role in the conflict. Almost 60,000 Australian troops served in rotation in South Vietnam over a 10-and-a-half year period, and nearly half of the 521 killed were conscripts. The National Service Act 1964 is amended later in 1973 to remove compulsory military training and National Service.

Australia sends 1000 troops to join UN peacekeeping forces in Somalia, the largest deployment since the Vietnam War.

On 11 September, attacks by terrorists in New York City, Washington, DC and Shanksville in the United States kill 2993 people. The attacks signal the beginning of the United States’ War on Terror, and Australia is at the forefront of the struggle, joining with the United States and its allies to contribute forces to the invasion of Afghanistan and later Iraq.

The Bali bombings on 12 October is one of the most horrific acts of terrorism that has come close to Australian shores. A total of 202 people (88 Australians) are killed in the tragedy, which takes place in the town of Kuta on the Indonesian island of Bali. A further 209 people are injured. A number of Indonesians are sentenced to death for their parts in the bombings and in October 2002 Abu Bakar Bashir, a leader of the Jemaah Islamiah organisation often accused of being behind the attacks, is charged over his alleged role in the bombing. In March 2005, Bashir was found guilty of conspiracy over the attacks. The Bali bombings 2002 are sometimes called ‘Australia’s September 11’ because of the large number of Australians killed in the attack.