The way the Australian Government is organized can be looked at in two ways. The first is federalism which organizes the way powers are distributed between the Australian Government and the state governments. The second is separation of powers into legislative, executive and judiciary branches of government. The Constitution supports the separation of powers in the way it sets out the roles of the branches of government.
Section 1 of the Australian Constitution sets up a democratic legislature, the bicameral Parliament of Australia. This is the Queen and two houses, the Senate and the House of Representatives. Section 51 of the Constitution sets out the Commonwealth Government's legislative powers and gives certain powers and responsibilities (known as "heads of power") to the federal government. All remaining responsibilities are kept by the six States. Each State has its own constitution, so that Australia has seven sovereign Parliaments, none of which can take over the powers of any other. The High Court of Australia rules on any arguments between the Commonwealth and the States, or among the States, about their powers.
The Commonwealth Parliament can propose changes to the Constitution. To become law, the proposals must be put to a referendum of all Australians of voting age. The changes must get a "double majority": a majority of all votes, and a majority of votes in a majority of States.
The Commonwealth Constitution also says that the States can agree to give any of their powers to the Commonwealth. This can be done by an amendment to the Constitution through a referendum. More commonly, if all the states agree, then all state and Commonwealth parliaments pass laws to allow the transfer. These "transfer" laws may have a "sunset clause". This is a part of the law that means the law is only in place for a certain time. After this, the original division of powers is put back.
Australia has several territories, three of which are self-governing: the Australian Capital Territory (ACT), the Northern Territory (NT) and Norfolk Island. The legislatures of these territories have powers given to them by the Commonwealth. The Commonwealth Parliament keeps the power to overturn territorial legislation and to give or take powers. While Australian citizens living in the Australian Capital Territory and the Northern Territory are represented in the Commonwealth Parliament, Norfolk Islanders are not.
Australia's other territories, (Jervis Bay, Christmas Island and the Cocos (Keeling) Islands) are not self-governing. Instead, these territories are governed by federal laws, with Christmas Island and the Cocos Islands also having local governments. The largely uninhabited Coral Sea Islands was set up as a Territory of the Commonwealth in 1969. The Ashmore and Cartier Islands has been a territory since 1933 run under the laws of the Northern Territory.
The federal nature of the Commonwealth and the structure of the Parliament of Australia were the subject of long negotiations among the colonies. The House of Representatives is elected on a basis which shows the different sized populations of the States. So New South Wales has 50 members while Tasmania has only five. But the Senate is elected on a basis of equality among the States: all States have 12 Senators, regardless of population. This was so the Senators of the smaller States could form a majority and change or even reject laws from the House of Representatives. The ACT and the NT elect two senators each.
The third level of government after Commonwealth and State/Territory is Local government. These are organized as shires, towns or cities. Local governments are made up of elected representatives (known as either councilor or alderman depending on the State), usually serving on a part-time basis.
Government is undertaken by three inter-connected arms of government:
The "Separation of powers" is the principle whereby the three arms of government do their activities separate from each other:
Before the Australia Act 1986, and matching legislation in the parliament of the United Kingdom, some Australian cases could be sent to the Judicial Committee of the Privy Council for final appeal. Australian law is now only decided on in Australia, and the High Court of Australia is the highest court of appeal. The possibility of the British Parliament making laws to overturn the Australian Constitution was also removed.
The Legislature makes the laws, and supervises the activities of the other two arms with a view to changing the laws if needed. The Australian Parliament is bicameral, made up of the Queen, a 76-member Senate and a 150-member House of Representatives. Twelve Senators from each state are elected for six-year terms, using proportional representation and the single transferable vote (known in Australia as "preferential voting", with half elected every three years.
There are also two senators elected by voters from the Northern Territory (and including the Indian Ocean Territories, Christmas Island and the Cocos (Keeling) Islands). Another two senators are elected by the voters of the Australian Capital Territory (including the Jervis Bay Territory). Senators from the territories are also elected using preferential voting, however, their term of office is not fixed: it starts on the day of a general election for the House of Representatives and ends the day before the next such election day.
The members of the House of Representatives are elected by preferential voting from single-member areas spread among the states and territories roughly in proportion to population. In ordinary legislation, the two chambers have the same powers, but all laws for spending money or charging taxes must come from the House of Representatives. In the Westminster system, the leader of the political party or group of parties that holds the support of a majority of the members in the House of Representatives is asked to form a government and is named Prime Minister.
The Prime Minister and the Cabinet are responsible to the Parliament, of which they must be members. General elections are held at least once every three years. The Prime Minister can advise the Governor-General to call an election for the House of Representatives at any time, but Senate elections can only be held within certain periods set out in the Constitution. The most recent general election was on 21 August 2010.
The Commonwealth Parliament and all the state and territory legislatures use the Westminster system. They have a recognised Leader of the Opposition, usually the leader of the largest party outside the government. There is also a Shadow Cabinet of Opposition members who "shadow" each member of the Ministry, asking questions on matters about the Minister's responsibilities. The government, because it has a majority of members in the lower house of the legislature, can usually pass its legislation and control the workings of the house. The Opposition can slow down the process and obstruct government business if it chooses. The day-to-day business of the house is usually worked out between a senior Minister, who holds the title Leader of the House, and an Opposition frontbencher known as the Manager of Opposition Business.
The Australian Constitution was written in 1901, when the Dominions of the British Empire were not independent countries, and does not use the words "head of state". In practice, the role of head of state of Australia is divided between two people, the Queen of Australia and the Governor-General of Australia. The Governor- General is appointed by the Queen on the advice of the Prime Minister of Australia. Though in many respects the Governor-General is the Queen's representative, and exercises various constitutional powers in her name, they are also independently vested with many important constitutional powers by the Constitution.