On the afternoon of Tuesday 11 June the Australian Electoral Commission removed from its website the list of closely contested House of Representatives seats. The last seat to be removed was Macquarie (NSW), covering the area of the Hawkesbury-Nepean rivers and the Blue Mountains. The final count was 48,661 votes for sitting Labor member Susan Templeman and 48,290 for the Liberal candidate Sarah Richards. Macquarie is an unlikely Labor seat and was a surprise Labor gain in July 2016 so the party felt relieved to hold on there so well.

We do not yet know the overall two-party preferred vote but it seems to be that the Coalition has 51.4% this year, compared with 50.4% in 2016, a swing against Labor of an even 1%, in effect accounted for entirely by the swing of 4.3% against Labor in Queensland. In that state, we do have the final two-party preferred vote and it is 1,653,261 for the Liberal National Party (58.4%) and 1,175,757 for Labor (41.6%).

We now know the final result in seats. It is 77 for the Coalition, 68 for Labor and six for the combination of all the rest, so 74 for the entire non-Coalition. In 2016, it was 76 for the Coalition, 69 for Labor and five for the combination of all the rest, so also 74 for the entire non-Coalition.

In 2016, there were two surprise Labor gains in Queensland, the seats of Longman, just north of Brisbane, and Herbert based on Townsville. In 2019, both returned to the Liberal National Party, Herbert with a massive, swing making it no longer marginal and Longman with a smaller swing that makes it the only Queensland LNP marginal seat. Labor now needs a swing of 3.3% to re-gain Longman – now my new median seat.

With those two LNP Queensland gains, why has Scott Morrison won only one more seat than Malcolm Turnbull did in 2016, 77 compared with 76? In net terms, the short answer is that Tony Abbott lost Warringah to Zali Steggall.

Outside of Queensland, everything cancelled out in party terms, both in votes and in seats. Labor gained from the Liberal Party Gilmore in New South Wales and Corangamite and Dunkley in Victoria but lost Bass and Braddon in Tasmania and Lindsay in New South Wales.

For the most part, the non-Queensland individual seat swings are explained in terms of what we psephologists call “retirement slump” and “sophomore surge”. For example, big swings to Labor in Higgins (inner Melbourne) and Curtin (inner Perth) are explained by the retirements of Kelly O’Dwyer and Julie Bishop, respectively. Both are exactly equivalent upper class seats, created in 1949 and always won by the candidate endorsed by the Liberal Party. The cancelling NSW gains/losses are explained by the retirements of Ann Sudmalis (Liberal) from Gilmore and Emma Husar (Labor) from Lindsay. Macquarie and Lindsay adjoin each other and Lindsay is a far more natural Labor seat than Macquarie – Lindsay having been lost by the machine’s sacking of Husar and Macquarie retained by the hard work of Templeman.

The American term “sophomore surge” refers to the ability of a first-term incumbent to perform well at the first election when he/she seeks re-election. Thus 2019 good Labor performances in Burt (WA), Cowan (WA), Lyons (Tasmania), Macarthur (NSW), Macquarie (NSW), Perth (WA) and Solomon (NT) are explicable  (in part, at least) in terms of “sophomore surge”.

Why so few net Coalition gains in seats, given the pro-Coalition swing in votes? Essentially, the answer lies in the strengthening of Coalition margins in what were its own marginal seats, especially in Queensland. On my post-2016 pendulum Labor needed a uniform swing of 1.3% to win government. It now needs 3.3%.

The new Liberal Party marginal seats are Bass (Tasmania, needing 0.5 for Labor to win), Chisholm (Victoria, 0.6), Boothby (SA, 1.4), Swan (WA, 2.8) Braddon (Tasmania, 3.1) and Longman (Queensland, 3.3). The Nationals now have no marginal seats. The only seat common to both my lists is Chisholm. Labor needed a 1.3% swing post-2016 and now needs only 0.6. So Morrison has gained a 1% swing but strengthened the government’s hold on office by 2%.

(Malcolm Mackerras is Honorary Fellow of Australian Catholic University. malcolm.mackerras@acu.edu.au. His website can be visited at www.malcolmmackerras.com)