The coup was thus a double decapitation: the Prime Minister and his too-powerful, micromanaging, forceful, feud-enmeshed chief of staff, Peta Credlin. Both were terminated with prejudice. Abbott's chief-of-staff Peta Credlin says she is considering offers to write a book. Credit:Alex Ellinghausen The catalyst for the coup, Foreign Affairs Minister Julie Bishop, had developed a loathing of Credlin. Like many in the parliamentary party, she came to believe that Credlin had to go, even if it meant getting rid of Abbott. So great was the animus towards Credlin among many people within the government that roughly half the backbench and half the ministry wanted to see her removed. It was Julie Bishop who delivered the blow.

This is not a question of blaming a female staffer for a male boss's failures. Abbott was the agent of his own demise. As much as I personally like the man, his performance on ABC's 7.30 last week was abysmal, the latest of many leaden efforts. If Credlin was such a brilliant political strategist, and the indefatigable engine of the Prime Minister's Office and leadership – which is how she saw herself – why has her boss, with all the leverage of the prime ministership, been sacked by his own colleagues after just two years in the job? In February, Credlin did not heed an explicit message given by the party that she should resign. When 39 Liberal backbenchers voted for a leadership spill, without even having a leadership contender, they did so in protest against the management style of Abbott and Credlin. But Abbott and Credlin couldn't change. This was a fundamental error of judgement by Abbott which proved fatal. He had been given a stark warning in February: get rid of your chief of staff and stop your office micro-managing the government, or you will be sacked. Abbott was told, explicitly, by numerous people including his political hero, John Howard, that Credlin had become Abbott's problem.

He chose the kamikaze option. His dependence on Credlin, and his belief in her, was so great and so obdurate that it contributed to a diminution of his standing in the party room, one pre-condition to his removal. Allowing a staffer to become a prime ministerial alter ego contributed to an element of inauthenticity​ to his leadership. This was picked up by the electorate, which has an excellent radar for such things. It may have been Malcolm Turnbull and Julie Bishop who unseated​ Abbott, but it was the public that sacked him. The public did not buy the carefully-packaged Abbott. The polls were clear about that for a long time. A similar problem haunted Julia Gillard after she became Prime Minister, and her persona became robotic. A sense of inauthenticity​ helped drive down her poll numbers, which caused her undoing. Gillard became robotic, and Abbott became sloganic​ (if I can invent a word).

After a period of chastened quiescence following the February upheaval, Abbott and Credlin reverted to doing much the same management that had existed prior to the revolt. This is what Turnbull pointedly alluded to on Monday night when he said he would run a "consultative" and "traditional" leadership. About two weeks ago, I formed a view that Abbott's leadership was terminal, not just because of the polls, but because I was getting messages from deep inside the government that morale was low. I was also hearing from inside the Prime Minister's Office that morale was sinking – a very bad portent. Twitter: @Paul_Sheehan_