The colleague, believing that Abbott could survive only if Peta Credlin's influence was removed, tried to persuade her that she should go even for her own sake: "One day, Tony will be sitting on a park bench in Manly feeding the pigeons and he will blame you."

It hasn't come to that yet but I expect it will in the end. But wrongly, as a way of avoiding his own responsibility.

For the moment, the former prime minister appears to be deep in depression, denial and delusion, still wondering what hit him, and why. He sees it as an ambush without warning, and a premeditated betrayal, rather than as final and unwilling act of exasperation by his colleagues after they had reluctantly concluded they could not win with a man of his character, style and incapacity to learn.

For the moment, as far as he is concerned, his was the greatest, not the worst, government in Australian history, undone by calculated betrayal and ambush, the more deplorable because it was without warning or rational explanation.

It is interesting that Savva, telling the story, with extra riveting detail in her compelling Road to Ruin, was not introducing new material in referring to the Manly bench and the pigeons. She had told it before, if without naming the Abbott colleague, in her regular newspaper column, but apparently without raising alarms about what or whether Savva knew about suggestions of an affair between Abbott and Credlin.

I have never believed in such an affair, though I had heard such speculations, including from senior bureaucrats. These might have owed something to the fact that Credlin was a confident, competent and attractive woman, with a loud and frank style, even with the prime minister himself. But it was not mere sexism, nor did it flow from some resentment or amazement about a woman in a senior executive role – something now commonplace, even in government.

Rather it flowed from an intimacy of interaction, including a fearless and, it seemed, often manipulative habit of Credlin of shouting at her boss and her colleagues. And of behaving badly, but without reproach from her boss, in the office that she managed, and in the cabinet among his colleagues.

Theirs was a professional relationship of the highest intimacy, in which she did not seem inhibited in any way about pressing her argument. Nothing odd about that: every prime minister since McMahon has had advisers who knew their bosses better than their spouses. Abbott was usually relaxed with senior women he trusted, but there was something special about the rapport with Credlin and the way she choreographed almost every part of his life. Abbott was strangely averse to conflict with her, particularly conscious of how much he relied upon her and owed her.

"Tony Abbott's overwhelming preoccupation was the wellbeing of his chief of staff, " Savva writes. "His concern for her happiness, his extreme protectiveness of her, his deferral to her, the transfer of his power to her – which allowed her to employ it ruthlessly – alienated his colleagues from cabinet ministers down, lost him the respect of business people who witnessed it, and forced the departure of experienced staff with expertise in policy, media and public administration."

This is not nudge-nudge for an affair, but a pointer to a relationship in which both parties had lost some of the detachment that makes for effective public partnership. It contributed to a folie-a-deux and a type of co-dependency that seems to have disabled both, but particularly Abbott. Savva was hardly the only one to notice.

Indeed, Credlin mostly seemed to relish the spotlight, her power, and some notoriety for ignoring convention. She raised eyebrows by her public profile, and the status she accorded herself, as a senior operator, but not an elected one, in the government. For many backbenchers and ministers her presence came to symbolise Abbott's weaknesses as a leader. They saw her removal, at whatever cost to Abbott, as essential to the survival of his government.

So was it all Credlin's fault? Or Abbott's, or both? Did the pair "destroy their own government"?

It goes without saying that Abbott, not Credlin, must accept responsibility anyway. Credlin, or her style, were not an asset to the Abbott government. But I do not think she bears the major blame for most of the disasters that struck it. Saying that is simply too convenient for others whose own damage was substantial.

Here are some things that did not destroy the Abbott government, though it destroyed others of recent memory:

The faults of the Abbott government were primarily political. They were consequences of poor political judgments by politicians. Credlin, as the most senior adviser to Abbott, may not be immune from criticism, but this is peculiarly a matter within the province of politicians, not minders.

She was not responsible for poor performance by Joe Hockey, Peter Dutton, Christopher Pyne, Kevin Andrews, David Johnson and Eric Abetz. Nor for strategic and political calls on the economy, on election promises, and on Abbott's decisions to ramp up a sense of crisis and fear on national security matters.

Disastrous captain's calls were usually pieces of Abbott mischief conceived and put into effect while her attention was distracted. Perhaps her rages were in part to scare him from such indiscipline.

The failure of the Abbott administration was not some dysfunction between the idea and the action, the policy and its execution, the intention and the reality, or the message and its communication. It died for bad, or at least ineffective, ideas, policies, intentions and messages.

Rudd and Gillard had failed, in part, because they could never get their acts together. Good ideas were often badly sold, and quickly abandoned or suffocated by other matters. For long periods, it seemed as if policies were devised primarily for anticipated public relations effect. But this was not Abbott's big problem.

He made some bad decisions from impulses to fire mischievous shots in the culture wars. He broke promises himself, having made broken promises at the centre of his attack on Gillard. He denied breach of promise, making himself look a liar. But what destroyed him with his colleagues, his party, business and the electorate flowed from a lack of effective attention to central problems, such as the economy and the Budget (different things) and bad, often primarily ideological policies, ill adapted to the problems at hand. Whether good or bad is a matter for opinion. But neither work if one cannot get them through parliament.

Abbott was hardly the first prime minister to face an obstructive senate. Politicians must deal with their circumstances as they find them. His incapacity to get out of his practical political problems reflect on his agility, leadership and management. Likewise, his tendency to be and play the warrior --- to turn everything, including the national defence, terrorism and the leadership of public bodies, into a partisan pissing contest – reflect on his character, and, at least to a degree his decency.

Savva puts in Credlin's, rather than Abbott's mouth, the idea that all appointments to public bodies, as to ministerial offices should be of "warriors" who will carry partisan political war into the camps of the enemy. But one knows that Credlin was merely implementing Abbott's will, not off on a frolic of her own. Likewise with the purge of senior public servants deemed to be identified with policies of the previous government, or extraordinary questions of the ABC such as "Whose side are you on?" It was clear, as with membership of Team Australia, that the side was not Australia's but Team Abbott.

Abbott had a tin ear for voter indulgence of his eccentricities and petty venalities. It was not for want of advice, including from colleagues who talked constantly with constituents. Or from professionals who constantly polled citizens or know their fields.

Credlin's character and personality did not complement Abbott's, though it was effective enough in opposition, when destruction was the aim in view. If she was professional, as she insists, her micromanaging, or "perfectionist" style, let alone her talent for little payback was not "best practice". It was not the primary problem. But it did underline the inadequacies of the leader, and of his warriors.

It must not be forgotten that Abbott got the sack from his own colleagues. One would sometimes get the impression that he was assassinated by a sniper bullet, with no one more surprised than Liberal MPs. He was sacked after an explicit warning only seven months before. He had acknowledged fault, expressed contrition and promised to change. But it soon became clear that he could not change, and that Credlin couldn't or wouldn't help him to.

Instead of going, as ministers and backbenchers thought necessary, she faded briefly from public view, but was soon again back in the middle of the scrum. What role this played in some of Abbott's later misjudgments, including over Bronwyn Bishop and Julie Bishop and same-sex marriage, is unclear, but it clearly did not restrain Abbott's suicidal impulses, perhaps in the name of death before dishonour.

Colleagues aplenty warned him that he faced another revolt from caucus, this time without the ministry bound in his favour. He ignored or discounted warnings. By the end, Blind Freddy knew what was coming. But Abbott was flummoxed, surprised and unprepared, having hardly bothered to monitor his numbers.

Since then he has been immersed in grief, delusion, incomprehension, desire for revenge and restoration to his rightful place. He and Credlin treat Turnbull and those about as the "enemy" and the usurpers. Obvious sabotage comes from his camp. That his professional adviser and friend continues to indulge such delusions may reflect kindness more than faith or hope. But realism was never her strong suit.