The good news for Turnbull is that each alternative leader is found to have a serious flaw. Tony Abbott, for example, "is well and truly yesterday's man". The list of flawed contenders also includes Finance Minister Mathias Cormann. Being a Senator he is, van Onselen suggests, "in the wrong chamber". But is this truly an objection? A possible Mathias Cormann ascension from the Senate, were it to occur, would not be unprecedented. It would mirror events which happened exactly half a century ago this year.

At the end of January 1968, Australia had a brand new prime minister in Senator John Gorton. Gorton had become leader of the federal Liberal Party following the disappearance before Christmas of his predecessor Harold Holt. Newly-elected prime minister John Gorton addresses the media after his party-room victory in 1968. Credit:John O'Gready Prime Ministers can come from the upper house but they cannot sit in it. So on February 1, 1968, Gorton resigned from the Senate. In a byelection held on February 24 he filled the vacancy in the House of Representatives caused by Holt's disappearance. The parallels between then and now are striking.

Harold Holt was the Malcolm Turnbull of his day. Together with his wife Zara he offered the promise of a fresh start after the aged Sir Robert Menzies retired in 1966 just as Malcolm and Lucy once embodied the prospect of an exhilarating era of innovation following Tony Abbott's stint as PM. Holt won a khaki election at the end of 1966 but he did poorly in a half Senate election held towards the end of 1967. Against a backdrop of government despondency the Canberra media corps began to detect leadership murmurs. The angst continued after Holt drowned at Cheviot Beach. Like Turnbull today, Holt seemed to have no clear successor as Prime Minister. There was no other Liberal Party member in the House of Representatives who came across as a viable replacement.

Faced with this situation the Liberals simply bypassed the House of Representatives. On January 9, 1968, they elected John Gorton, a cabinet minister who was government leader in the Senate, as their new leader. There is nothing to prevent today's crop of Liberals from following the Gorton scenario. Turnbull is chronically hapless but, like Holt before him, he is not seen as having a viable successor. As commentators such as Peter van Onselen freely acknowledge, his lower house colleagues who may have leadership ambitions – Abbott, Bishop, Morrison, Dutton - turn out to be unacceptable to either their party colleagues or to the wider public. But that still leaves the Senate and Mathias Cormann. He can do a Gorton on his colleagues. There is no doubting Cormann's credentials for the top job. For almost five years as Finance Minister he has been involved at the highest level in the federal budgetary process and in government decision making.

He is leader of the Government in the Senate and has served as Acting Prime Minister. Cormann is skilled and respected as a negotiator and deal maker. His work ethic is prodigious. As a foreign-born person he can draw on themes of diversity and resilience in developing the grand narrative that a good Prime Minister has to command. Cormann, along with Peter Dutton, currently forms a Praetorian Guard protecting Turnbull against a final leadership meltdown. But in imperial Rome, in the days of its decadence, it sometimes fell to the Praetorian Guard to slay the Emperor. Turnbull would immediately resign as federal member for Wentworth should he lose the Liberal leadership and yet the Gorton precedent suggests that this is not an inhibiting factor at all. John Gorton had no connection at all with Holt's old seat of Higgins in Melbourne and yet victory in the resulting byelection was no problem for him.

In a similar way, Cormann, who would need to move to the House of Representatives, could be slotted into the seat of Wentworth as Turnbull's replacement. Fixed boundaries mean little to him. He comes from a region of Europe that has been swapped between Belgium and Germany according to the fortunes of war. He studied in England before migrating to, and flourishing in, Perth. Every time Cormann moves to a new city he fits in with the local lingo and mores. Sydney's eastern suburbs would be no exception. He would speedily shake off the dreaded tag of being a blow-in. He would be an entirely credible candidate and member for Wentworth. Leaving the Senate would remove the only serious objection to his becoming our next prime minister. And so after 50 years the Gorton precedent is suddenly very much alive again. It is certainly worthy of consideration. Stephen Holt is a Canberra writer.