In the first of my two Wentworth articles for Switzer before polling day “How will Australia’s wealthiest electorate vote?” I wrote of the high number of renters in Wentworth and then this: “For that reason, Wentworth is not “blue ribbon Liberal” to my way of thinking. It used to be (in the fifties), when its boundaries were roughly the same as those of the present state seat of Vaucluse. That state seat is a genuine “blue ribbon Liberal” electoral district. The federal seat of Wentworth is not.”

For that reason, my first instinct when doing a post-election analysis is to look at the vote in Vaucluse (all of which being in Wentworth), compared with those in the state seats of Coogee, Heffron and Sydney combined, parts of each of which are in Wentworth.

The latest count has Kerryn Phelps on a total two-candidate preferred vote of 37,774, being composed of 19,152 from polling places in the Coogee, Heffron or Sydney state electoral districts, 15,067 from Vaucluse and 3,555 being votes for which residence cannot be ascertained, these latter being mainly postal votes. By contrast, Dave Sharma has 17,706 from Vaucluse, 13,087 from Coogee-Heffron-Sydney and 5,427 votes for which residence cannot be ascertained. That makes a total of 36,220 two-candidate preferred votes.

In other words, my point is made. Vaucluse is blue-ribbon Liberal but Wentworth is not. So why did media commentators so regularly describe Wentworth wrongly in this regard? The answer is two-fold.

First, on the 2016 federal general election figures, Wentworth was the eighth strongest Coalition win, being bested only by the ultra-safe Victorian Nationals seats of Murray, Mallee and Gippsland and the genuine blue-ribbon Liberal seats of Bradfield, Curtin, Farrer and Mitchell. The point here is that Turnbull enjoyed an enormous personal vote in Wentworth.

Second, two historical propositions were asserted. The first was correct. It was true that the modern Liberal Party (founded in 1944) had never lost before in Wentworth. Twice it came close to losing (Eric Harrison in 1943 and Turnbull in 2004) but it did not actually lose on either occasion. Harrison was deputy leader of the Liberal Party from 1944 to 1956 when he left politics.

The second historical proposition was wrong. It was not true that the principal non-Labor party had won Wentworth at every election since Federation. Walter Moffitt Marks had won Wentworth as a Nationalist in 1919, 1922, 1925 and 1928 but in 1929 he was one of seven conservative rebels, who brought down the Bruce-Page government in a parliamentary vote. Of the seven seats in question, Wentworth was the one with the weakest Labor vote in 1928. (Its boundaries then were essentially the same as the present state seat of Vaucluse).

In 1929, there was a snap election for the House of Representatives only. Labor withdrew its candidate and Labor supporters were asked to vote for the now independent Marks on the ground that he had “saved federal arbitration”. Consequently Marks had his last win in Wentworth as an independent, strongly supported by Labor.

Readers of this website will be aware that I have long been very critical of Turnbull. However, when it came to the point my advice to the Federal Parliamentary Liberal Party was clear. It was “Keep Turnbull”. That advice was contained in my article “Who should lead the Liberal Party into the next federal election?” which was published on this website on Wednesday August 22.

They were mad to sack Turnbull on Friday August 24. They must have known he would resign Wentworth very soon afterwards. They must also have known of the serious possibility that the Liberal Party would lose the Wentworth by-election. If I knew that surely they too must have known it.

Malcolm Mackerras is Honorary Fellow of Australian Catholic University.