Editing Australian Senate (section)

==Membership==
Under sections 7 and 8 of the Australian Constitution:<ref>{{cite web|url=http://www.aph.gov.au/Senate/pubs/odgers/chap0402.htm |title=Chapter 4, Odgers' Australian Senate Practice |publisher=Aph.gov.au |date=2 February 2010 |access-date=17 July 2010 |url-status=dead |archive-url=https://web.archive.org/web/20110321210201/http://www.aph.gov.au/senate/pubs/odgers/chap0402.htm |archive-date=21 March 2011 |df=dmy }}</ref>
* The Senate must comprise an equal number of senators from each original state,
* each original state shall have at least six senators, and
* the Senate must be elected in a way that is not discriminatory among the states.

These conditions have periodically been the source of debate, and within these conditions, the composition and rules of the Senate have varied significantly since federation.

===Size and nexus===
Under [[Section 24 of the Constitution of Australia|Section 24 of the Constitution]], the number of members of the House of Representatives has to be "as nearly as practicable" double the number of senators.

The reasons for the nexus are twofold: a desire to maintain a constant influence for the smaller states, and maintain a constant balance of the two Houses in the event of a joint sitting after a double dissolution. A [[1967 Australian referendum (Parliament)|referendum in 1967]] to eliminate the nexus was rejected.

The size of the Senate has changed over the years. The Constitution originally provided for six senators for each state, resulting in a total of 36 senators.

The Constitution permits the Parliament to increase the number of senators, provided that equal numbers of senators from each original state are maintained; accordingly, in 1948, Senate representation was increased from 6 to 10 senators for each state, increasing the total to 60.

In 1975, the two territories, the [[Northern Territory]] and the [[Australian Capital Territory]], were given an entitlement to elect two senators each for the first time, bringing the number to 64.<ref>{{Cite Legislation AU|Cth|num_act|sota1973408|Senate (Representation of Territories) Act 1973}}</ref> The senators from the Northern Territory also represent constituents from Australia's Indian Ocean Territories ([[Christmas Island]] and the [[Cocos (Keeling) Islands]]), while the senators from the Australian Capital Territory also represent voters from the [[Jervis Bay Territory]] and since 1 July 2016, [[Norfolk Island]].<ref>{{cite web |url=http://www.aec.gov.au/Enrolling_to_vote/special_category/Norfolk_Island_electors.htm |title=Norfolk Island Electors |publisher=Australian Electoral Commission |date=2016 |access-date=6 August 2016 |archive-date=15 June 2016 |archive-url=https://webarchive.nla.gov.au/awa/20160615042855/http://www.aec.gov.au/Enrolling_to_vote/Special_Category/Norfolk_Island_electors.htm |url-status=live }}</ref>

The latest expansion in Senate numbers took place in 1984, when the number of senators from each state was increased from 10 to 12, resulting in a total of 76 senators.<ref name = "electing">Department of the Senate, ''Senate Brief'' No. 1, [http://www.aph.gov.au/Senate/pubs/briefs/brief01.htm 'Electing Australia's Senators'] {{webarchive |url=https://web.archive.org/web/20070829204046/http://www.aph.gov.au/Senate/pubs/briefs/brief01.htm |date=29 August 2007 }}. Retrieved August 2007.</ref>

===Term===
Senators normally serve fixed six-year terms (from 1 July to 30 June). At most federal elections, the seats of 40 of the 76 senators (half of the 72 senators from the six states and all four of the senators from the territories) are contested, along with the entire House of Representatives; such an election is sometimes known as a half-Senate election. The seats of senators representing states elected at a half-Senate election are not contested at the next election, provided it is a half-Senate election. However, under some circumstances, the entire Senate (and the House of Representatives) is dissolved, in what is known as a [[double dissolution]]. Following a double dissolution, half the senators representing states serve terms ending on the third 30 June following the election (two to three years) and the rest serve a five to six-year term. [[Section 13 of the Constitution of Australia#Allocation of terms|Section 13 of the Constitution]] requires the Senate to allocate long and short terms amongst its members. The term of senators representing a territory expires at the same time as there is an election for the House of Representatives.<ref>{{Cite Legislation AU|Cth|act|coaca430|Commonwealth of Australia Constitution Act|13}}</ref>

Section 13 of the Constitution requires that in half-Senate elections, the election of State senators shall take place within one year before the places become vacant. The actual election date is determined by the Governor of each State, who acts on the advice of the State Premier. The Governors almost always act on the recommendation of the Governor-General, with the last independent Senate election writ being issued by the Governor of Queensland during the [[Gair Affair]] in 1974.

Slightly more than half of the Senate is contested at each general election (half of the 72 state senators, and all four of the territory senators), along with the entire House of Representatives. Except in the case of a double dissolution, senators for the states are elected for fixed terms of six years, commencing on 1 July following the election, and ceasing on 30 June six years later.

The term of the four senators from the territories is not fixed, but is defined by the dates of the general elections for the House of Representatives, the period between which can vary greatly, to a maximum of three years and three months. Territory senators commence their terms on the day that they are elected. Their terms expire the day prior to the following general election day.<ref>{{Cite Legislation AU|Cth|num_act|sota1973408|Senate (Representation of Territories) Act 1973|6}}</ref>

While there is no constitutional requirement for the election of senators to take place at the same time as those for members of the House of Representatives, the government usually synchronises the dates of elections for the Senate and House of Representatives. However, because their terms do not coincide, the incoming Parliament will for some time comprise the new House of Representatives and the old Senate, except for the senators representing the territories, until the new senators start their term on the next 1 July.

Following a double dissolution, all 76 senators face re-election. If there is an early House election outside the 12-month period in which Senate elections can occur, the synchronisation of the election will be disrupted, and there can be half-Senate elections without a concurrent House election. The last time this occurred was on [[1970 Australian Senate election|21 November 1970]].

===Quota size===
The number of votes that a candidate must receive to be elected to the senate is referred to as a "quota". The quota is worked out by dividing the number of formal votes by one more than the number of vacancies to be filled and then adding one to the result.<ref>{{Citation |title=The Senate count process |url=https://aec.gov.au/Voting/counting/files/senate-count-process.pdf |type=Pamphlet |archive-url=https://web.archive.org/web/20200325041928/https://aec.gov.au/Voting/counting/files/senate-count-process.pdf |publisher=Australian Electoral Commission |archive-date=25 March 2020}}</ref> The 2019 senate election was a half senate election, so 6 senate vacancies were contested in each state. At this election, the quotas in each state were:
{| class="wikitable"
|-
! State !! 2019 quota !! % of the NSW 2019 quota !! 2016 double dissolution quota<ref>{{Cite web |date=9 August 2016 |title=Senate quota |url=https://results.aec.gov.au/20499/Website/SenateStateProvisionalQuota-20499.htm |url-status=live |archive-url=https://web.archive.org/web/20160921065032/http://results.aec.gov.au/20499/Website/SenateStateProvisionalQuota-20499.htm |archive-date=21 September 2016 |access-date=21 March 2022 |website=Australian Electoral Commission Tally Room – 2016 Federal Election |publisher=Australian Electoral Commission}}</ref>
|-
| NSW || 670,761 || 100% || 345,554
|-
| Vic || 534,207 || 80% || 269,250
|-
| Qld || 414,495 || 62% || 209,475
|-
| WA || 206,661 || 31% || 105,091
|-
| SA || 156,404 || 23% || 81,629
|-
| Tas || 50,285 || 7% || 26,090
|}

===Proportional representation of the states vs one vote one value===
Each state elects the same number of senators, meaning there is equal representation for each of the Australian states, regardless of population, so the Senate, like many upper Houses, does not adhere to the principle of [[one vote one value]]. [[Tasmania]], with a population of around 500,000, elects the same number of senators as [[New South Wales]], which has a population of more than 8 million. 

{| class="wikitable"
|-
! State/Territory/Commonwealth !! 2021 Census population<ref>{{Cite web |date=28 June 2022 |title=Population: Census |url=https://www.abs.gov.au/statistics/people/population/population-census/2021 |url-status=live |archive-url=https://web.archive.org/web/20240219235324/https://www.abs.gov.au/statistics/people/population/population-census/latest-release |archive-date=19 February 2024 |access-date=7 March 2024 |website=Australian Bureau of Statistics – Population: Census 2021}}</ref><ref>{{Census 2021 AUS |id=SAL90004 |quick=on |name=Norfolk Island |access-date=7 March 2024}}</ref><ref>{{Census 2021 AUS |id=LGA51710 |name=Christmas Island |quick=on |access-date=7 March 2024}}</ref><ref>{{Census 2021 AUS |id=SAL90003 |name=Jervis Bay |quick=on |access-date=7 March 2024}}</ref><ref>{{Census 2021 AUS |quick=on |id=901021002 |name=Cocos (Keeling) Islands |access-date=7 March 2024}}</ref>!! Population per senator 
|-
| [[New South Wales]] || 8,339,347 || 694,945
|-
| [[Victoria (state)|Victoria]] || 6,503,491 || 541,957
|-
| [[Queensland]] || 5,156,138 || 429,678
|-
| [[Western Australia]] || 2,660,026 || 221,668
|-
| [[South Australia]] || 1,781,516 || 148,459
|-
| [[Tasmania]] || 557,571 || 46,464
|-
| [[Northern Territory]] (including [[Christmas Island]] and [[Cocos (Keeling) Islands]]) || 234,890 || 117,445
|-
| [[Australian Capital Territory]] (including [[Jervis Bay Territory]] and [[Norfolk Island]]) || 456,687 || 228,343
|-
| [[Australia]] || 25,422,788 || 334,510
|}

The proportional election system within each state ensures that the Senate incorporates more political diversity than the lower house ([[Australian House of Representatives|House of Representatives]]), which has historically been a [[Two-party system|two party]] body. The elected membership of the Senate more closely reflects the first voting preference of the electorate as a whole than does the composition of the House of Representatives, despite the large discrepancies from state to state in the ratio of voters to senators.<ref>{{Cite journal|last=Lijphart|first=Arend|date=1 November 1999|title=Australian Democracy: Modifying Majoritarianism?|journal=Australian Journal of Political Science|volume=34|issue=3|pages=313–326|doi=10.1080/10361149950254|issn=1036-1146}}</ref><ref>{{cite conference|url=http://www.aph.gov.au/Senate/pubs/pops/pop34/a01.pdf|title=Overview: Institutional Design and the Role of the Senate|last1=Sawer|first1=Marian|conference=Representation and Institutional Change: 50 Years of Proportional Representation in the Senate|volume=34|editor=Marian Sawer |editor2=Sarah Miskin|date=1999|pages=1–12|archive-url=https://web.archive.org/web/20110117111841/http://aph.gov.au/Senate/pubs/pops/pop34/a01.pdf|archive-date=17 January 2011|url-status=dead|df=dmy-all}}</ref><ref>{{Cite news|url=https://theconversation.com/just-how-representative-are-the-houses-of-parliament-of-how-australians-vote-62160|title=Just how representative are the houses of parliament of how Australians vote?|last=Trudgian|first=Tim|work=The Conversation|access-date=2018-05-30|language=en|archive-date=21 September 2018|archive-url=https://web.archive.org/web/20180921125212/https://theconversation.com/just-how-representative-are-the-houses-of-parliament-of-how-australians-vote-62160|url-status=live}}</ref> This often means that the composition of the Senate is different from that of the House of Representatives, contributing to the Senate's function as a [[Upper house|house of review]].

With proportional representation, and the small majorities in the Senate compared to the generally larger majorities in the House of Representatives, and the requirement that the number of members of the House be "nearly as practicable" twice that of the Senate, a joint sitting after a double dissolution is more likely than not to lead to a victory for the House over the Senate. When the Senate had an odd number of senators retiring at an election (3 or 5), 51% of the vote would lead to a clear majority of 3 out of 5 per state. With an even number of senators retiring at an election, it takes 57% of the vote to win 4 out of 6 seats, which may be insurmountable. This gives the House an advantage in joint sittings but not in ordinary elections, where the Senate may be too evenly balanced to get House legislation through.

A party does not need the support of the Senate to form government (needing only a majority in the House of Representatives), however the Senate can block supply, effectively preventing the government from lawfully spending money. Whether a government facing a Senate that blocks [[Confidence and supply|supply]] is obliged to either resign or call an election was one of the major disputes of the [[1975 Australian constitutional crisis|1975 constitutional crisis]]. However, even where the Senate does not block supply, they can still use their power to frustrate the legislative agenda of the government.

===Parties===
{{see also|Independent politicians in Australia#Senate}}
Political parties have played a major role in the operations of the Senate throughout its history.{{sfn|Bach|2003|p=144}} Some framers of the constitution intended that senators would give first priority to the interests of their states, placing state considerations above party interests. However, others involved in drafting the constitution – including [[Alfred Deakin]], [[Isaac Isaacs]], and [[H. B. Higgins]] – correctly predicted that party considerations would soon dominate state interests.{{sfn|Bach|2003|pp=146–147}} 

[[Party discipline]] was important in the Senate from the first parliament, most notably with the formation of an [[Australian Labor Party Caucus|Australian Labor Party caucus]] after the inaugural [[1901 Australian federal election|1901 election]] which required its members to vote in line with decisions of the majority. A two-party system became ensconced in both houses of parliament following the [[Liberal Party (Australia, 1909)|"fusion" of the non-Labor parties]] in 1909, largely as a response to the discipline of the ALP.{{sfn|Bach|2003|p=144-145}} Votes on party lines soon became a regular feature of debate, with corresponding criticisms that the Senate had merely become a rubber stamp for the government rather than filling the role of a states' house.{{sfn|Bach|2003|p=146}}

The "block" voting system used for the Senate prior to electoral reform in 1948 contributed to uneven party representation in the Senate, with the party securing the majority of votes in a state typically winning all that state's Senate seats. After the emergence of the two-party system, there were only two elections between 1910 and 1949 where the government formed in the House of Representatives did not also hold a majority in the Senate. In both cases ([[1913 Australian federal election|1913]] and [[1929 Australian federal election|1929]]) the government lasted only a single term.{{sfn|Bach|2003|p=49}} The system produced "extreme and wildly fluctuating results".{{sfn|Bach|2003|p=75}} On five occasions, the government won all available seats at half-Senate elections; consecutive landslide victories could resulted in the opposition being reduced to a handful of seats, such as when the ALP was reduced to a single Senate seat after the [[1919 Australian federal election|1919 election]].{{sfn|Bach|2003|p=76}} These outcomes, while still uncommon, led the Senate to be perceived as a weak institution serving as a rubber stamp and contributed to calls for reform.{{sfn|Bach|2003|pp=76–77}}

The system of proportional representation passed in 1948 and implemented at the [[1949 Australian federal election|1949 election]] resulted in a more even balance of party representation.{{sfn|Bach|2003|p=78}} A largely unintended consequence of the reforms was the emergence of minor parties as a political force in the Senate, ending a period of 40 years where every elected senator had been a member of either the ALP or the various anti-Labor parties.{{sfn|Bach|2003|p=79}} The first minor party to achieve prominence and obtain the [[Balance of power (parliament)|balance of power]] in the Senate was the [[Democratic Labor Party (Australia, 1955)|Democratic Labor Party]] (DLP), formed after the [[Australian Labor Party split of 1955|ALP split of 1955]].{{sfn|Bach|2003|p=80}} The [[Australian Democrats]] and the [[Australian Greens]] have also held the balance of power at various points.{{sfn|Bach|2003|p=51}} This marked the start of a pattern of non-government control of the Senate, where neither the government nor the opposition held a majority of seats and the government was reliant on minor party and independent senators to pass legislation.{{sfn|Bach|2003|p=52}} Since 1962, the government has secured a Senate majority on only three occasions: after the [[1975 Australian federal election|1975]], [[1977 Australian federal election|1977]] and [[2004 Australian federal election|2004 elections]].<ref>{{cite news |url=https://www.aph.gov.au/binaries/senate/pubs/pops/pop52/23_having_the_numbers_means_not_having_to_explain.pdf |title=Having the Numbers Means Not Having to Explain: The Effect of the Government Majority in the Senate |first=Harry |last=Evans |year=2009 |work=Papers on Parliament |volume=52 |publisher=Parliament of Australia |pages=151–1633}}</ref>

===Casual vacancies===
{{see also|Casual vacancies in the Australian Parliament|List of Australian Senate appointments}}
Section 15 of the Constitution provides that a [[Casual vacancies in the Australian Parliament|casual vacancy]] of a State senator shall be filled by the State Parliament.<ref>{{Cite Legislation AU|Cth|act|coaca430|Commonwealth of Australia Constitution Act|15}}</ref> If the previous senator was a member of a particular political party the replacement must come from the same party, but the State Parliament may choose not to fill the vacancy, in which case Section 11 requires the Senate to proceed regardless. If the State Parliament happens to be in recess when the vacancy occurs, the Constitution provides that the State Governor can appoint someone to fill the place until fourteen days after the State Parliament resumes sitting.<ref>{{Cite Legislation AU|Cth|act|coaca430|Commonwealth of Australia Constitution Act|11}}</ref>