Formidable arithmetic challenge
Yesterday, apparently, the Prime Minister told his troops that Labor had the “very formidable arithmetic challenge” of getting 17 seats.
I had been under the assumption that the number of seats Labor needed to win government was 16, and not 17. And so I had my own formidable arithmetic challenge: 16 or 17?
The 2004 election saw a House of 150 seats with 87 Coalition members, 60 Labor members, and three independents. Immediately following the 2004 election, to win government outright — ie. to have 76 seats in a house of 150 — Labor needed to win 16 additional seats. The mathematics is simple: 60 + 16 = 76.
There has been one by-election since 2004, in the seat of Werriwa. That by-election saw Chris Hayes (Labor) replace Mark Latham (Labor). It did not affect the number of seats Labor needs to win.
The have also been redistributions in New South Wales, Queensland and the Australian Capital Territory since the 2004 election. The redistributions saw no change to the number of seats in the House (150). One Coalition seat in New South Wales (Gwydir) was abolished and a notionally Coalition seat (Flynn) was created in Queensland. This does not affect the number of seats Labor needs to win.
According to the Mackerras Pendulum, the redistributions also saw two seats notionally change sides. Parramatta, currently held by Labor, becomes a nationally Liberal seat. And, Macquarie, currently held by the Liberals, becomes a notionally Labor seat. Because these notional moves cancel each other out, they do not affect the number of seats Labor needs to win.
In the seat of Calare, independent member Peter Andren has announced he will not stand for election in Calare in 2007. Instead he will contest the senate election. This changes Calare from an independent seat to a notionally Coalition seat. As a consequence, it does not change the number of seats Labor currently holds, nor the number of seats Labor needs to win government. However, it increases by one the number of seats the Coalition can lose before it loses government in its own right from 12 to 13.
As a result of the above, the Coalition notionally holds 88 seats. Labor notionally holds 60 seats. and the independents hold 2. The seats held by each party are set out in the following table. The notional seats are in italics.
| The Coalition | Labor | Independents |
| Aston, Vic; Barker, SA; Bass, Tas; Bennelong, NSW; Berowra, NSW; Blair, Qld; Bonner, Qld; Boothby, SA; Bowman, Qld; Braddon, Tas; Bradfield, NSW; Calare, NSW; Canning, WA; Casey, Vic; Cook, NSW; Corangamite, Vic; Cowper, NSW; Curtin, WA; Dawson, Qld; Deakin, Vic; Dickson, Qld; Dobell, NSW; Dunkley, Vic; Eden-Monaro, NSW; Fadden, Qld; Fairfax, Qld; Farrer, NSW; Fisher, Qld; Flinders, Vic; Flynn, Qld; Forde, Qld; Forrest, WA; Gilmore, NSW; Gippsland, Vic; Goldstein, Vic; Greenway, NSW; Grey, SA; Groom, Qld; Hasluck, WA; Herbert, Qld; Higgins, Vic; Hinkler, Qld; Hughes, NSW; Hume, NSW; Indi, Vic; Kalgoorlie, WA; Kingston, SA; Kooyong, Vic; La Trobe, Vic; Leichhardt, Qld; Lindsay, NSW; Longman, Qld; Lyne, NSW; Macarthur, NSW; Mackellar, NSW; Makin, SA; Mallee, Vic; Maranoa, Qld; Mayo, SA; McEwen, Vic; McMillan, Vic; McPherson, Qld; Menzies, Vic; Mitchell, NSW; Moncrieff, Qld; Moore, WA; Moreton, Qld; Murray, Vic; North Sydney, NSW; O’Connor, WA; Page, NSW; Parkes, NSW; Parramatta, NSW; Paterson, NSW; Pearce, WA; Petrie, Qld; Riverina, NSW; Robertson, NSW; Ryan, Qld; Solomon, NT; Stirling, WA; Sturt, SA; Tangney, WA; Wakefield, SA; Wannon, Vic; Warringah, NSW; Wentworth, NSW; Wide Bay, Qld | Adelaide, SA; Ballarat, Vic; Banks, NSW; Barton, NSW; Batman, Vic; Bendigo, Vic; Blaxland, NSW; Brand, WA; Brisbane, Qld; Bruce, Vic; Calwell, Vic; Canberra, ACT; Capricornia, Qld; Charlton, NSW; Chifley, NSW; Chisholm, Vic; Corio, Vic; Cowan, WA; Cunningham, NSW; Denison, Tas; Fowler, NSW; Franklin, Tas; Fraser, ACT; Fremantle, WA; Gellibrand, Vic; Gorton, Vic; Grayndler, NSW; Griffith, Qld; Hindmarsh, SA; Holt, Vic; Hotham, Vic; Hunter, NSW; Isaacs, Vic; Jagajaga, Vic; Kingsford Smith, NSW; Lalor, Vic; Lilley, Qld; Lingiari, NT; Lowe, NSW; Lyons, Tas; Macquarie, NSW; Maribyrnong, Vic; Melbourne Ports, Vic; Melbourne, Vic; Newcastle, NSW; Oxley, QLD; Perth, WA; Port Adelaide, SA; Prospect, NSW; Rankin, Qld; Reid, NSW; Richmond, NSW; Scullin, Vic; Shortland, NSW; Swan, WA; Sydney NSW; Throsby, NSW; Watson, NSW; Werriwa, NSW; Wills, Vic | Kennedy, Qld; New England, NSW |
| TOTAL: 88 seats | TOTAL: 60 seats | TOTAL: 2 seats |
Back to our “very formidable arithmetic challenge”. As far as I can tell, Labor still needs 16 more seats to win government in its own right (not the 17 reported).
Also, if the Coalition loses between 13 and 15 14 seats, and the number of independents remains unchanged at 2, the independents will decide which party forms government.
Update 8.45am 13/6: having thought about this some more, Labor would form minority government with an additional 15 seats. With an addition 15 seats Labor would have 75 seats, the Coalition 73, and the independents 2.
Even with the support of the independents, there is no way the Coalition could guarantee supply after providing one of its number as Speaker. After providing for the Speaker, such a Coalition minority government would proceed to lose every vote in the House 74-75. Section 40 of the Australian Constitution provides:
40. Questions arising in the House of Representatives shall be determined by a majority of votes other than that of the Speaker. The Speaker shall not vote unless the numbers are equal, and then he shall have a casting vote.
If the Coalition cannot guarantee supply, even with the support of the independents, it cannot form government. If the independents did not support Labor, the Governor General would need to call another election, as neither side can guarantee supply without the support of the independents. Only Labor can guarantee supply with the support of the independents.
So, Labor really only needs 15 additional seats to win government.
With the hypothetical uniform swing, using the election calculator, if Labor won 51.3 per cent of the TPP vote share it would win 75 seats. The last seat to fall under that swing would be Bennelong.