The country has maintained a stable liberal democratic political system under its Constitution, the world's tenth oldest, since Federation in 1901.
Australia is the world's sixth oldest continuous democracy and largely operates as a two-party system in which voting is compulsory.
However, in accordance with Westminster system, there is no strict separation between the executive and legislative branches, with ministers required to also be members of the legislature.
[6] The Australian system of government combines elements derived from the political systems of the United Kingdom (fused executive, constitutional monarchy) and the United States (federalism, written constitution, strong bicameralism), along with distinctive local features, and has therefore been characterised as a "Washminster mutation".
The federal nature and the structure of the Parliament of Australia were the subject of protracted negotiations among the colonies during the drafting of the Constitution.
[17] The federal government can also significantly influence state legislation by making tied grants (money which comes with certain conditions).
This is a significant power due to high levels of vertical fiscal imbalance arising because of the limited revenue raising capabilities of the states.
However, the prime minister, the cabinet and the other principles of responsible government are not explicitly mentioned in the document, along with most of the realities of exercise of executive power.
The monarch is the symbolic head of Australia and is ceremonially involved in all branches of the government, as a constitutive part of Parliament, formal holder of executive power and the person in whose name most criminal offences are brought.
[35] These are rarely exercised, but during the Australian constitutional crisis of 1975 Governor-General Sir John Kerr used them to dismiss the prime minister during a parliamentary deadlock over supply.
[38] The proposal would have removed references to the Queen from the Constitution and replaced the governor-general with a president nominated by the prime minister, but subject to the approval of a two-thirds majority of both houses of Parliament.
The prime minister is selected from the House, needing the support of the majority of members in order to be invited to form a government.
[47] Each chamber of Parliament has equal powers, with the exception that the Senate may not introduce "money bills" (new taxes or laws authorising expenditure).
[48] However, the Senate can still block supply (the annual bill authorising government expenditure), but this has only happened once, during the 1975 Australian constitutional crisis.
[49][50] Parliamentarians belong to either the government, the opposition or sit on the cross-bench (which includes independents and members of minor parties).
Finally, the bottom layer includes public servants, police, government departments and independent statutory bodies who directly implement policy and laws.
In practice however, this definition is difficult to apply as many actions by executive agencies are wide ranging, binding and conducted independently of Parliament.
[56] The Federal Executive Council is a formal body which exists and meets to give legal effect to decisions made by the Cabinet, and to carry out various other functions.
[59] Cabinet meetings are strictly private and occur once a week where vital issues are discussed and policy formulated.
[60] The Constitution of Australia does not explicitly mention Cabinet; it existing solely by convention, with its decisions not in and of themselves having legal force.
In practice, the Federal Executive Council meets solely to endorse and give legal force to decisions already made by the Cabinet.
[63] Prior to the 2007 general election, the then Leader of the Opposition, Kevin Rudd, said that he and he alone would choose the ministry should he become prime minister.
[65] While Caucus rules are not public,[66] the Sydney Morning Herald has reported that ministerial positions are allocated to the Left and Right factions on a proportional basis according to their representation in Parliament.
[80] Thomas Playford served as Premier of South Australia and leader of the Liberal and Country League (LCL) from 5 November 1938 to 10 March 1965 (26 years).
Labor winning government in New South Wales on 25 March 2023 marked the second time in history that the Australian Labor Party gained control of the entirety of Mainland Australia at the federal and mainland state levels simultaneously (leaving Tasmania as the only state with a Liberal government), a feat that had last been achieved in 2007.
[81][82] This would last until 24 August 2024 when Labor lost government in the Northern Territory to the Country Liberal Party (CLP) opposition.
The Australian party system has been described by political scientists as more ideologically driven than other similar anglophone countries such as the United States and Canada.
[94] In early Australian political history, class interests played a significant role in the division between the then-democratic socialist Australian Labor Party and a series of anti-Labor parties drawing on the liberal and conservative traditions (the predecessors of the modern Coalition of the Liberals and Nationals).
[99][100] Parliamentary Labor Party members such as Andrew Leigh have argued that the ALP should be reclassified as social liberal.
[103][104] In recent decades there has been a marked shift amongst the Australian electorate in providing their first preference votes to candidates not belonging to either of the two major parties.