Whoever won the funny lines contest, the conclusion we can draw from this call is the same.

Bishop has said that after listening to an angry Abbott tirade she replied, "So I take it I can't count on your vote?"

What was said next varies according to which side of the conversation is telling the tale. Abbott has told colleagues that he said, "Why would I vote for Malcolm in a skirt?" And then abruptly hung up.

Julie Bishop and Tony Abbott during a division in the House of Representatives in December 2018. Credit:Alex Ellinghausen

It was as far as she got. Abbott cut her off. "What about you do me the courtesy of being a loyal deputy?" He was still fuming about the collapse of his own prime ministership three years earlier. He blamed Bishop for colluding against him.

Hi Tony, it's Julie Bishop," began the call. Long silence. Malcolm Turnbull's prime ministership was collapsing. Bishop had decided to run for the leadership. She was making every call herself, even the difficult ones, to ask for support. No intermediaries, no numbers men.

Indeed, Cormann would become a decisive force for its next, fatal turn, and Turnbull's most bitter disappointment.

Abbott wouldn't accept a diplomatic post; Turnbull wouldn't give him a cabinet one. It would take some sort of intervention to find a solution. But Cormann had tried several times already and his energy for the task was exhausted. The Liberals were fated to complete the cycle.

Greiner asked senior ministers to get involved, too. For instance, during an overseas trip with Mathias Cormann in June 2017 he said to the Finance Minister: "You have to find a way to shut Tony up. It doesn't matter whether it's ambassador to Kazakhstan, put him in cabinet, whatever. It has to stop."

"Malcolm declined to engage on the issue," he has told colleagues "He thought he'd win on his merits. And Tony didn't really want to try for a resolution either. Both put themselves ahead of the party."

The Liberal party national president, Nick Greiner, made a concerted effort to break the cycle. But the former NSW premier discovered that there was a distinct lack of real interest in pursuing reconciliation.

It was August 2018, but the anger of the coup against Abbott in September 2015 was still live and raw. And that coup was partly a consequence of Abbott's coup against Turnbull in 2009. Like the Labor party before it, the Liberals found themselves in a long and demented cycle of vengeance.

Turnbull has since said that Cormann didn't contest his characterisation of the insurgents as "terrorists".

But the account given by others in the room is starkly different. "We are past all that," Cormann said, in the recounting of others who were there. "You can't describe 35 members of the party room as terrorists."

The reply from Cormann? Turnbull has told his allies and confidantes that Cormann said, "We have to give in to the terrorists." Turnbull says that he has a note of the remark.

Cormann, the Leader of the Government in the Senate and the man he regarded as his most constant confidante and counsellor, had come to give Turnbull the hard news. Together with two other Liberal senators, Jobs Minister Michaelia Cash and Communications Minister Mitch Fifield, he told Turnbull on Wednesday, the day after the initial spill, that his leadership was irretrievable. Turnbull had won the spill against Dutton by 48 votes to 35.

In the parliamentary corridors outside the prime minister's suite, the conservatives who had barely tolerated Turnbull for three years were going office to office gathering the ammunition, the signatures on a petition, to end his leadership. "You can't give in to terrorists."

"Mathias, these people are terrorists," the then prime minister told Cormann over and over as he pleaded for his job in the final 48 hours of his prime ministership.

The others talked him around, in the Cormann side's version of the meeting, "telling Turnbull that there was no need to get the Governor-General on the phone." They assured him they were trying to find a resolution to the situation.

In the Cormann side's account, the prime minister performed a dramatic flourish – he produced his phone and said he was going to call the Governor-General. "Peter Cosgrove knows he can't swear him in because he has a Section 44 issue," said Turnbull, in the accounts given by people in the room. "I'll get Peter on the phone now and he will tell you himself." Even if the party voted Dutton in, the Governor-General wouldn't be able to swear him in. In the Turnbull telling, this didn't occur.

"You can't install Dutton," said Turnbull. Dutton's wife's childcare business received a federal government subsidy, and Dutton was a director of her company. MPs and senators can be ineligible if they are in any business relationship with the Commonwealth.

The prime minister raised the constitutional question mark over Peter Dutton. He even invoked the prospect that the Governor-General would not swear in Dutton even if the party elected him leader, all sides to the conversation agree.

Cormann conveyed that, since the first spill, cabinet ministers who'd voted for Turnbull had come to him to say that the prime minister was too badly damaged. "In my judgement you have lost the majority."

Turnbull's prime ministership ended as it began – on the conservatives' terms. It was not the angrily obvious Abbott who moved to strike the fatal blow but the quietly determined Dutton.

It was the inevitable conclusion to the Faustian bargain Turnbull had made to win the prize. He had sold his soul for his supernatural powers and, just as an evil angel foretold to Dr Faustus in Marlowe's play, when his time was up he would "tumble in confusion".

Turnbull told colleagues that he was thinking of calling an early election, perhaps the Friday of that week. Anything might have happened.

But Cormann's view was that the longer the government continued with an injured PM, the worse the situation would get. He wanted certainty for the party, the government and the country. By the end of the week.

Turnbull's anger at Cormann today stems from his view that, as a former Turnbull aide says, "Cormann could have stopped it. All he had to do was to tell Dutton and a couple of others, 'F--- off, I'm with him'," indicating the prime minister.

They were alarmed that Turnbull might bring the head of state into a party leadership contest, potentially turning a leadership crisis into a constitutional one.

He'd decided four months earlier, in April, that he would likely challenge Turnbull by the end of the year. The government, clinging to its majority of one, had been behind in every opinion poll since the last election. Dutton couldn't see how Turnbull could win. And a growing body of opinion in the party agreed with him. The government reeled from one disaster to another.

Turnbull had managed some serious accomplishments. He'd taken a party in despair, and out of cash, and given it hope and energy.

When he took the leadership of the parliamentary party, Tony Nutt replaced Brian Loughnane as the leader of the organisational wing only to discover that the Liberal party was broke.

Astonishingly, for his first months in the job, Nutt was unpaid. The Liberal party could not afford to pay its federal director.

The elevation of Turnbull restored the flow of support, donations and votes.

But as the electorate discovered that Turnbull was there to enact Abbott's agenda on key issues – "Tony Abbott in a nicer suit" as one wit cuttingly put it – the enthusiasm ebbed.

Turnbull contributed $1.75 million of his personal fortune to the party's 2016 election campaign. Today the party is again short of cash as it prepares for a federal election in May.

Loading

And for every success there was a setback. For every Snowy 2.0 triumph there was a bonking ban embarrassment, for every reform to the Marriage Act there was a citizenship crisis, for every piece of deft diplomacy in managing Donald Trump there was a failure in diplomacy managing Tony Abbott.

Turnbull told himself that the government was running well and that the polls were slowly improving. There was everything to be gained by sticking with his leadership.

Dutton couldn't be sure he could win an election, but as the party increasingly lost confidence in Turnbull, the conservatives decided that Turnbull had no political judgement, that the polls would never recover and that they had nothing to lose by changing to Dutton. "At least we'll go down on our own terms," one conservative said.

Dutton played to this sentiment: "I know what I stand for and I won't compromise on that," he told colleagues, "a bit like John Howard".

But the conservatives lapped up Dutton's tough guy rhetoric. The weight of his undersized antique desk, the desk that Dutton thought had once been Howard's, pressed down on his knees, and to him it must have seemed the Howard mantle itself.

By the middle of last year Dutton was not ready to challenge and not entirely committed to do so, and he continued to work closely with Turnbull even as he weighed his decision. But three factors converged to force events to their denouement, to bring on what Scott Morrison would later deride as a "muppet show".

The Longman byelection on July 28 was a threshold moment. It was one of five byelections on so-called Super Saturday. The seat just north of Brisbane was held by Labor's Susan Lamb, forced to resign by the High Court when it ruled that as a British citizen she was ineligible to sit in Parliament. The Liberal National Party ran hard to win the seat. And, for a moment, there was a prospect that it would.

It would have been the first time in a century that a government had won a seat from the opposition at a byelection. Turnbull overplayed his hand, declaring that "the contest is between me and Bill Shorten."

So when Labor reclaimed the seat, the prime minister had no one to blame.

Opposition Leader Bill Shorten and then-Prime Minister Malcolm Turnbull in February 2018. Credit:Alex Ellinghausen

The LNP's share of the vote in Longman fell by a jolting 10 percentage points. Over two elections it had fallen a sickening 16 percentage points.

If the government went to an election and lost just one-fifth as many votes in its other Queensland seats, it would be wiped out. The Longman result drained hope from the government.

Second, energy policy, once again, created the opportunity for upheaval. Ever since Abbott broke Australia's bipartisan consensus by dumping the Howard policy for an emissions trading scheme, energy and carbon policy have been the killing field in Australian political leadership.

Turnbull and his energy minister Josh Frydenberg did a painstaking job of crafting an energy policy, the National Energy Guarantee, as a fragile compromise between all parts of the Coalition. Turnbull and Frydenberg even managed to have it negotiated through the party room. Eight MPs had spoken against it, but if party discipline had held it very likely would have made it into law.

But, of course, it didn't, and, with some conservatives threatening to cross the floor in the House to oppose it, the policy shattered. Australia remained without an energy policy and was about to lose the prime minister who had tried to give it one.

Turnbull dumped the policy – technically, he announced a "stay" on the policy, just as Kevin Rudd had announced a delay in his climate change policy when his colleagues were coming for him.

"I did that so I couldn't be blamed for bringing the government down over the NEG," Turnbull later explained. "I did everything possible to keep the government together."

But, in truth, the core of disgruntled conservatives was not to be appeased and not to be dissuaded. "There was probably nothing Malcolm could have done to hold the right at bay," one prominent conservative said after the event.

Loading

Third, Turnbull chose the timing. With the conservative movement rallying around Dutton as its champion, Turnbull decided to pre-empt the coming challenge.

The prime minister guessed that Dutton wasn't quite ready, and he was right. He had resolved to strike but was still gathering numbers. He was still some weeks away.

Turnbull took the initiative and brought on a surprise spill motion. This was startling to everyone except his deputy, Bishop, his numbers man, Craig Laundy, and the whips, who'd needed to prepare ballot papers.

It was especially shocking to Cormann. "You should have seen Mathias' face," said another MP. "It was white. He was stunned."

Cormann felt wounded that he'd been excluded from this momentous decision. After working as Turnbull's confidential consigliere, conservative praetorian guard and Senate manager, he felt that he'd earned the right to be consulted. And if he had been? He would have urged Turnbull not to do it.

But once done, it exposed the deep fissure in the government. The conservatives had their blood up, and Morrison's smaller support group was manoeuvring to make sure the damage to Turnbull was irreparable.

After surviving the first spill by 48 to 35, Turnbull tried to see if Dutton could be contained. A remarkably calm and conciliatory Turnbull visited Dutton in his office immediately after the spill and encouraged him to stay in the Cabinet. "You've done an incredible job in the portfolio, let's put this behind us and get on with it."

Dutton has told colleagues that Turnbull also dangled the deputy leader's job in front of him, the job Bishop held at the time. Turnbull has denounced this as a lie.

Dutton declined. It was not viable for him to stay in Turnbull's cabinet, he said. It was the next day, Wednesday, that Cormann threw his weight behind Dutton and Turnbull lost his last conservative bulwark. He was finished.

Once Turnbull came to this conclusion himself on Thursday, all thinking turned to how to thwart Dutton. Turnbull gave Morrison and Bishop absolution to make their own bids for the leadership.

He set up a delaying mechanism to give them time – he said he'd only call another party room meeting if presented with a petition with 43 signatures, a majority of the party members, on it.

He didn't realise that Morrison's supporters had a bid already well under way. Bishop was late to the race, without realising that she'd already lost. She was the party's only popular prospect. But even as she was making her calls, her own faction, the moderates, guided by Christopher Pyne, Simon Birmingham, Marise Payne and Paul Fletcher, decided the imperative was not to elect one of their own but to block Dutton.

"If we make Julie leader, do you think the conservatives will stop throwing rocks?" one of the moderates' leaders said at the time. The tactics of terrorism, and even the anticipated threat of it, were paramount in their thinking.

Outgoing PM Malcolm Turnbull addresses the media after the partyroom meeting for the leadership spill, with his wife Lucy, daughter Daisy and grandchildren Jack and Alice on August 24, 2018. Credit:Alex Ellinghausen

The moderates decided that the only way to defeat Dutton was to back Morrison, which is what they did. For a man with perhaps a dozen supporters in the party to win a ballot of 45 was, as one of his supporters later boasted, "miraculous".

To Dutton's disappointment he was not to wear Howard's mantle. And he later discovered that his prized desk probably hadn't actually belonged to the former leader.

One of the younger conservatives stalking the corridors seeking signatures to end Turnbull's term was Victorian senator James Paterson. As he took the petition from office to office he passed the moderate MP Julia Banks and gave her a friendly "Hi Julia, how are you?"

Banks replied, "Well you've really f---ed this up".

Paterson: "There's a lot of it going on."

Incoming Prime Minister Scott Morrison and newly elected deputy leader of the Liberal Party Josh Frydenberg on August 24, 2018 Credit:Dominic Lorrimer

Two months later, after Turnbull had quit Parliament and brought on the Wentworth byelection that cost the government its majority, Bill Shorten stood up in Parliament and asked Scott Morrison his ritual question, the great mystery of the unexplained Morrison prime ministership: "Why is Malcolm Turnbull gone but you're still here?"

Morrison replied that he would bear responsibility for voter anger: "I'm very, very happy to stand up as leader of the Liberal Party and cop it on the chin."

Morrison will go to the May election leading with his chin.

This is the final part of the Endgame series. Read the rest of the series here.