The federal government is separated into three branches:
The legislature: the bicameral Parliament, defined in section 1 of the constitution as comprising the Queen (represented by the Governor-General), the Senate, and the House of Representatives;
The executive: the Federal Executive Council, in practice the Governor-General as advised by the Prime Minister and Ministers of State;[84]
The judiciary: the High Court of Australia and other federal courts, whose judges are appointed by the Governor-General on advice of the Council.
Malcolm Turnbull, Prime Minister of Australia
Peter Cosgrove, Governor-General of Australia
In the Senate (the upper house), there are 76 senators: twelve each from the states and two each from the mainland territories (the Australian Capital Territory and the Northern Territory).[85] The House of Representatives (the lower house) has 150 members elected from single-member electoral divisions, commonly known as "electorates" or "seats", allocated to states on the basis of population,[86] with each original state guaranteed a minimum of five seats.[87] Elections for both chambers are normally held every three years, simultaneously; senators have overlapping six-year terms except for those from the territories, whose terms are not fixed but are tied to the electoral cycle for the lower house; thus only 40 of the 76 places in the Senate are put to each election unless the cycle is interrupted by a double dissolution.[85]
Australia's electoral system uses preferential voting for all lower house elections with the exception of Tasmania and the ACT which, along with the Senate and most state upper houses, combine it with proportional representation in a system known as the single transferable vote. Voting is compulsory for all enrolled citizens 18 years and over in every jurisdiction,[88] as is enrolment (with the exception of South Australia).[89] The party with majority support in the House of Representatives forms the government and its leader becomes Prime Minister. In cases where no party has majority support, the Governor-General has the constitutional power to appoint the Prime Minister and, if necessary, dismiss one that has lost the confidence of Parliament.[90]
There are two major political groups that usually form government, federally and in the states: the Australian Labor Party and the Coalition which is a formal grouping of the Liberal Party and its minor partner, the National Party.[91][92] Within Australian political culture, the Coalition is considered centre-right and the Labor Party is considered centre-left.[93] Independent members and several minor parties have achieved representation in Australian parliaments, mostly in upper houses.
Following a partyroom leadership challenge, Julia Gillard became the first female Prime Minister in June 2010.[94] The most recent federal election was held on 7 September 2013 and resulted in a majority government for the Coalition. Liberal Party leader Tony Abbott was sworn into office as Prime Minister by the Governor-General of Australia on 18 September. In September 2015, Malcolm Turnbull successfully challenged Abbott for leadership of the Coalition, and was sworn in as Prime Minister on the 15th.[95] With five Prime Ministers in as many years between 2010 and 2015, with most of those leadership changes occurring through leadership spills rather than general elections, Australia has been described as the "coup capital of the democratic world".[96]