The 2017 Western Australian state election was held on Saturday 11 March 2017 to elect members to the Parliament of Western Australia, including all 59 seats in the Legislative Assembly and all 36 seats in the Legislative Council. The eight-and-a-half-year two-term incumbent Liberal–WA National government, led by Premier Colin Barnett, was defeated in a landslide by the Labor opposition, led by Opposition Leader Mark McGowan.

Labor won 41 of the 59 seats in the Legislative Assembly—a 12-seat supermajority. This was WA Labor's strongest performance in a state election at the time, and formed the largest majority government and seat tally in Western Australian parliamentary history until that point. Additionally, Labor exceeded all published opinion polling, winning 55.5 percent of the two-party-preferred vote from a state record landslide 12.8-point two-party swing.Labor 55.5% 2PP vote and +12.8-point 2PP swing sourced from Antony Green's temporary estimate within provided ABC link published 30 March 2017, which states "The two-party-preferred count is based on estimates for Baldivis, Moore and Roe. – Final 2017 WA Election Results plus a New Electoral Pendulum: Antony Green ABC 30 March 2017 It was the worst defeat of a sitting government in Western Australia, as well as one of the worst defeats of a sitting state or territory government since Federation.

Labor also became the largest party in the Legislative Council with 14 of the 36 seats. The Labor government thus required at least five additional votes from non-government members to pass legislation.

Results Legislative Assembly

+Legislative Assembly (IRV) – Turnout 86.90% (CV) PartyVotes%SwingSeats +/–   Labor 557,794 42.20 9.07 41 20   Liberal 412,710 31.23 15.88 13 18   Greens 117,723 8.91 0.51 0   National 71,313 5.40 0.66 5 2   One Nation 65,192 4.93 New 0   Christians 27,724 2.10 0.29 0   Shooters, Fishers, Farmers 17,317 1.31 New 0   Micro Business 13,211 1.00 New 0   Matheson for WA 6,145 0.47 New 0   Animal Justice 2,836 0.21 New 0   Flux the System! 2,188 0.17 New 0   Family First 1,443 0.11 0.49 0   Socialist Alliance 694 0.05 New 0   Liberal Democrats 561 0.04 New 0   Independents 24,327 1.84 1.07 0   Other 462 0.04 New 0  Formal votes 1,321,640 95.46 1.46  Informal votes 62,860 4.54 1.46  Total 1,384,500 59  Registered voters / turnout 1,593,222 86.90 2.31 Two-party-preferred vote Labor 733,738 55.5 12.8 Liberal 587,353 44.5 12.8

The four main media networks covering the election, the ABC, Sky News, Seven News and Nine News, all called the election for Labor within two hours after polls closed. McGowan succeeded Barnett to become the 30th Premier of Western Australia.

By the morning of 12 March, two thirds of votes had been counted and seven lower house seats were still in doubt, showing that Labor had won at least 36 seats, well above the 30 required for a majority, which the ABC predicted would increase to 41. Meanwhile, the Liberals and WA Nationals had won only 10 and five seats respectively, with a further three expected to be retained by the Liberals.

The swing against the government affected traditionally safe seats. Consequently, six government ministers lost their seats in the Legislative Assembly while one lost his seat in the Legislative Council.

The Labor landslide was built primarily on a near-sweep of Perth. Labor took 34 of the capital's 43 seats on a swing of 13.6 points, accounting for nearly all of its majority. By comparison, it had gone into the election holding 17 seats in Perth. According to the ABC's Antony Green, the 10 percent swing Labor needed to make McGowan premier was not nearly as daunting as it seemed on paper. Green noted that several Liberals in outer suburban seats sat on inflated margins. Additionally, Green argued that the one vote one value reforms of 2008, which allowed Perth to elect over 70 percent of the legislature, proved to be a boost for Labor in 2017. Green noted that when Labor last governed from 2001 to 2008, it did so in a legislature where voters in country seats had twice the voting power of voters in a Perth-based seat.

Seats changing parties Seat Pre-2017 Swing Post-2017 Party Member Margin Margin Member Party Balcatta  Liberal Chris Hatton 7.1 12.9 5.8 David Michael Labor  Belmont  Liberal Glenys Godfrey 1.0 12.4 11.4 Cassie Rowe Labor  Bicton  Liberal Matt Taylor1 10.0 13.0 2.9 Lisa O'Malley Labor  Bunbury  Liberal John Castrilli 12.2 23.0 10.8 Don Punch Labor  Burns Beach  Liberal Albert Jacob2 11.3 13.9 2.5 Mark Folkard Labor  Darling Range  Liberal Tony Simpson 13.1 18.9 5.8 Barry Urban Labor  Forrestfield  Liberal Nathan Morton 2.2 11.6 9.4 Stephen Price Labor  Jandakot Liberal Joe Francis 18.3 19.4 1.0 Yaz Mubarakai Labor Joondalup Liberal Jan Norberger 10.4 11.0 0.6 Emily Hamilton Labor Kalamunda  Liberal John Day 10.3 12.7 2.5 Matthew Hughes Labor  Kalgoorlie National Wendy Duncan 3.2 n/a 6.2 Kyran O'Donnell Liberal  Kingsley Liberal Andrea Mitchell 14.0 14.7 0.7 Jessica Stojkovski Labor Morley  Liberal Ian Britza 4.7 16.2 11.4 Amber-Jade Sanderson Labor  Mount Lawley  Liberal Michael Sutherland 8.9 12.9 4.0 Simon Millman Labor  Murray-Wellington Liberal Murray Cowper 12.0 13.4 1.4 Robyn Clarke Labor Perth  Liberal Eleni Evangel 2.8 14.6 11.8 John Carey Labor  Pilbara National Brendon Grylls 11.5 13.8 2.3 Kevin Michel Labor  Southern River  Liberal Peter Abetz 10.9 18.8 7.9 Terry Healy Labor  Swan Hills  Liberal Frank Alban 3.7 18.3 14.5 Jessica Shaw Labor  Wanneroo  Liberal Paul Miles 11.0 18.2 7.3 Sabine Winton Labor 

1 Matt Taylor was the member for the seat of Bateman, but contested Bicton after losing preselection to Dean Nalder, the member for the abolished seat of Alfred Cove. 2 Albert Jacob was the member for the abolished seat of Ocean Reef, but instead contested Burns Beach, a seat containing much of the same territory.

Members listed in italics did not contest their seat at this election. Labor also retained two seats—Collie-Preston and West Swan—which were notionally Liberal-held after the redistribution. The Liberals retained Hillarys, which was being contested by the incumbent MLA Rob Johnson as an independent.

Legislative Council

+Legislative Council (STV/GVT) – Turnout 87.00% (CV) PartyPrimary votes%SwingSeats +/-   Labor 544,938 40.41 7.90 14 3   Liberal 360,235 26.71 20.91 9 8   Greens 116,041 8.60 0.39 4 2   One Nation 110,480 8.19 New 3 3   National 59,776 4.43 0.45 4 1   Shooters, Fishers, Farmers 31,924 2.37 0.59 1   Christians 26,209 1.94 0.01 0   Liberal Democrats 23,848 1.77 New 1 1   Animal Justice 14,838 1.10 New 0   Family First 11,279 0.84 0.53 0   Daylight Saving 9,209 0.68 New 0   Micro Business 7,484 0.55 New 0   Flux the System! 5,934 0.44 New 0   Matheson for WA 5,270 0.39 New 0   Fluoride Free WA 4,327 0.32 New 0   Socialist Alliance 1,367 0.10 New 0   Independents 15,516 1.15 0.53 0   Other 482 0.03 New 0  Formal votes 1,348,675 97.29 0.13  Informal votes 37,480 2.70 0.13  Total 1,386,155 36  Registered voters / turnout 1,593,222 87.00 2.20

Labor became the largest party in the Legislative Council with 14 of the 36 seats. The Labor government will require at least five additional votes from non-government members to pass legislation.

On 4 April, the Western Australian Electoral Commission conducted a recount of 2013 election results to fill two casual vacancies for the remainder of the 2013–17 term caused by the resignation and subsequent election to the Legislative Assembly of Amber-Jade Sanderson (Labor) in East Metropolitan and Peter Katsambanis (Liberal) in North Metropolitan. The vacancies were filled by Bill Leadbetter (Labor) and Elise Irwin (Liberal), who will first sit in the Legislative Council on 11 May 2017.

Date of election

On 3 November 2011, the Government of Western Australia introduced fixed four-year terms for the Legislative Assembly, with the elections to be held on the second Saturday in March.‘So when is the next election?’: APH.gov.au 1 September 2016 The first election under the new law was the 2013 election. Previously, under electoral reforms of the Burke Government in 1987, four-year maximum terms were adopted for the Legislative Assembly, and fixed four-year terms for the Legislative Council.Phillips, Harry C. J. Electoral Law in the State of Western Australia: An Overview . Western Australian Electoral Commission, 2013. , page 113 (pdf 126). Retrieved 10 March 2017

Campaign The Western Australian National Party led by Brendon Grylls, who retook the leadership in August 2016, ran on a policy to increase the tax on every tonne mined from $0.25 to $5 for BHP and Rio Tinto. The big mining companies ran an advertising campaign against the policy, while a poll conducted found that 39.4% of voters surveyed supported the policy, 37.1% opposed and 23.5% were undecided.

The Liberal Party undertook a preference deal with One Nation during the elections, saying the party held less extreme views than it did in the 1990s. Some One Nation candidates were against the preference deal with the Liberal Party.

One Nation ran on opposing privatisation and the National party mining taxes.

Seats held

Lower house At the 2013 election, Labor won 21 seats, the Liberals won 31 seats and the Nationals won 7 seats. No seats were won by independents.

On 15 April 2016, the Liberal member for Hillarys, Rob Johnson, resigned from the Liberals to sit as an independent, leaving the government with 30 seats in the lower house.

Upper house At the 2013 election, the Liberals won 17 seats, Labor won 11 seats, the Nationals won five seats, the Greens won two seats and the Shooters and Fishers won one seat.

Western Australia's Legislative Council was divided into six regions at the time. Three were based in Perth, while three were rural. Each region elected six members to the Legislative Council. These areas were not of similar population sizes, with rural areas having received from one and a half to about six times the effective membership of the metropolitan regions.

The Western Australian rural population dropped from about 12.1% to 10.7% of the state's enrolled electors after the 2008 election. Election analyst Antony Green predicted this would make it more difficult for the Liberals or Labor (who typically perform better in Perth than rural areas) to increase their presence within the Legislative Council.

Redistribution

A redistribution of electoral boundaries for the lower house was completed on 27 November 2015. This resulted in a net gain of one seat for the Liberals from Labor. The Liberal seats of Alfred Cove, Eyre and Ocean Reef, the Labor seat of Gosnells and the National seat of Wagin were abolished. Five new seats were created (or re-created): the notionally Liberal seats of Bicton (mostly replacing Alfred Cove) and Burns Beach (mostly replacing Ocean Reef), the notionally Labor seats of Baldivis (created from parts of Kwinana and Warnbro) and Thornlie (replacing Gosnells), and the notionally National seat of Roe (merging Wagin and Eyre). The Labor seats of Collie-Preston and West Swan became notionally Liberal.

Retiring MPs Members who did not re-nominate at the 2017 election:

Liberal John Castrilli MLA (Bunbury) – announced 14 March 2016 Kim Hames MLA (Dawesville) – announced 2 August 2014 Liz Behjat MLC (North Metropolitan) – lost preselection Barry House MLC (South West) – announced 27 October 2015

National Wendy Duncan MLA (Kalgoorlie) – announced 4 December 2015 Terry Waldron MLA (Wagin) – announced 25 November 2014

Electoral pendulums The following Mackerras pendulums work by lining up all of the seats according to the percentage point margin post-election on a two-candidate-preferred basis, grouped as marginal, safe etc. as defined by the Australian Electoral Commission.

Pre-election pendulum