Following the recent publication of draft new boundaries for Victoria, South Australia and the Australian Capital Territory, we now have some idea of what the state of play will be going into the next election, albeit that said boundaries are now subject to a process of public submissions and possible revision. The only jurisdictions that will retain their boundaries from the 2016 election will be New South Wales and Western Australia, redistributions for Queensland, Tasmania and the Northern Territory having been done and dusted since the last election.
The next election will be for a House of Representatives of 151 seats, ending a period with 150 seats that began in 2001. This is down to rounding in the formula by which states’ populations are converted into seat entitlements, which on this occasion caused Victoria to gain a thirty-seventh seat and the Australian Capital Territory to tip over to a third, balanced only by the loss of a seat for South Australia, which has now gone from thirteen to ten since the parliament was enlarged to roughly its present size in 1984.
The changes have been generally favourable to Labor, most noticeably in that the new seat in Victoria is a Labor lock on the western edge of Melbourne, and a third Australian Capital Territory seat amounts to three safe seats for Labor where formerly there were two. The ACT previously tipped over for a third seat at the 1996 election, but the electorate of Namadji proved short-lived, with the territory reverting to two seats in 1998, and remaining just below the threshold ever since. The Victorian redistribution has also made Dunkley in south-eastern Melbourne a notionally Labor seat, and has brought Corangamite, now to be called Cox, right down to the wire. Antony Green’s and Ben Raue’s estimates have it fractionally inside the Coalition column; mine has it fractionally tipping over to Labor.
The table at the bottom is a pendulum-style listing of the new margins, based on my own determinations for the finalisised and draft redistributions. The outer columns record the margin changes in the redistributions, where applicable (plus or minus Coalition or Labor depending on which side of the pendulum they land). Since I have Cox/Corangamite in the Labor column, I get 77 seats in the Coalition column, including three they don’t hold (Mayo, held by Rebekha Sharkie of the Nick Xenophon Team, and Indi and Kennedy, held by independents Cathy McGowan and Bob Katter), and 74 in the Labor column, including two they don’t hold (Andrew Wilkie’s seat of Clark, as Denison will now be called, and Adam Bandt’s seat of Melbourne).