There is a sense that Scott Morrison’s government has reached the point of no return as the realisation dawns that Bill Shorten’s Opposition is now the government-in-waiting.

The near 20 per cent shift against the Liberals in Wentworth is the harbinger of impending doom for the Coalition government. The third Liberal prime minister in five years admits he has a significant challenge ahead but says he’s “getting on with the job”. Evidence shows he’s not up to it – and frankly nobody is. Because what is required is a complete rebuild of the edifice that is the federal Liberal Party. That sort of remake can only be undertaken in Opposition, with time to sort out differences and test policy directions that are acceptable to what John Howard called “mainstream Australia”. That was the judgement of the people after the political shambles that was the Rudd–Gillard–Rudd years.

If the latest Newspoll is any guide, a majority of voters across the nation share the judgement of the good burghers of Wentworth – perhaps not as emphatically, but it would take a uniform swing of only 0.7 per cent to see a change of government. In this week’s poll the swing was about 4.5 per cent, which translates to a loss of 20 seats. Just two months into his prime ministership, Morrison’s approval has fallen into negative territory.

It’s true opinion polls take only the pulse – they are indicative not predictive – but Wentworth was a taste of the real thing. And a sure sign that Liberals everywhere know it was Morrison’s absence last Sunday from the Liberals’ campaign launch for the Victorian election on November 24. He admits he wasn’t invited. He visited the state the day after and was quizzed about his no-show. The venue of the news conference was Princetown on the “Shipwreck Coast”, almost poetic in its irony.

The writs for the Victorian election have been issued and the time for niceties is over. The state Liberals have made the judgement that the prime minister’s presence would only remind everyone of their colleagues’ dysfunction in Canberra.

The Victorians’ judgement was vindicated on Tuesday when the latest Newspoll of the state voting intention had them in the same parlous position, trailing Daniel Andrews’ Labor government by eight points. Another explanation for Morrison’s non-appearance and half-hearted assurances that he would “cross paths” with state leader “Matty” Guy at some time in the campaign was that he does not want to be tarred with their loss. “Neither of them wants to be associated with each other,” was the comment of one federal Victorian Liberal MP.

But there is no getting away from the view held in the state divisions of the party that the Canberra infighting is doing them great damage. New South Wales state Liberal parliamentarian Peter Phelps summed up the sentiment in a widely reported comment on Twitter last week: “The best thing the Fed Libs could do now is deliberately engineer a vote of no confidence in the Reps; go to an early election; get smashed; and stop driving down the vote in NSW and Vic in the lead up to our state elections. PS this is the near universal view of my colleagues.”

As if on cue, two dumped prime ministers jumped into frame. Tony Abbott called for the warring factions to sheath their swords now that Malcolm Turnbull has been despatched. He also inferred that, like John Howard, he would be better at managing his colleagues’ differences in a “second stint” as leader. The not quite “politically dead” Turnbull was on a delicate mission to Indonesia. He was there to repair the damage done by his successor’s extremely unwise and crude play for votes in the dying days of the Wentworth campaign.

“The best thing the Fed Libs could do now is deliberately engineer a vote of no confidence in the Reps; go to an early election; get smashed; and stop driving down the vote in NSW and Vic in the lead up to our state elections.”

Morrison put on a brave face in the party room after the Wentworth poll, saying that his announcement about possibly moving the Australian embassy to Jerusalem actually saved some votes in the electorate, which has a strong Jewish presence. The published opinion polls of the seat and the postal votes suggest otherwise. But what Morrison wouldn’t have bargained for was Turnbull publicly criticising his thought bubble and comparing it unfavourably with how he, Turnbull, handled the issue while in government.

Turnbull told the media in Bali he decided “after very careful and considered advice ... a policy that is well over 40 to 50 years old should remain exactly the same as it is”. He said, “There is no question, were that move to occur, it would be met with a very negative reaction” in the most-populous Muslim nation on earth – Indonesia. At risk: economic, strategic and trade cooperation with our nearest powerful neighbour.

Morrison pleaded that “no decision has been made” and he would always act in the national interest. “Let me stress,” he assured, “Australia decides what our foreign policy is, and only Australia.”

In a week in which Shorten gave a highly acclaimed speech on foreign policy, attended by a bevy of embassy heavyweights and other high-powered observers, the chaos was manna from heaven for the ALP. The Opposition leader said “Liberal disunity and division” is making us “a laughing stock around the world”. He asked people to “imagine what the Indonesians think. Here’s Malcolm Turnbull, who they last met as prime minister, now no longer prime minister, going up to explain that the current prime minister didn’t mean what he said.”

For good measure “the small-minded, obsessive conservative lobby with its anti-Turnbull mania”, as Paul Kelly describes them, chimed in. Three told The Australian the dumped PM was out of line. Senator James Paterson accused Turnbull of failing in his obligation to uphold the policy of the current Australian government. Barnaby Joyce took a similar view, never mind that Turnbull was actually cleaning up a shambles Joyce himself feared could harm trade. But Queensland LNP member Luke Howarth – the man prepared to move a spill motion against Turnbull that precipitated the events that led to the coup – takes the cake. He said, “Australia should go ahead with the move despite the threat of economic consequences.”

Joyce, who makes no secret of ambitions to return to the Nationals’ leadership, has never forgiven Turnbull for his scathing criticism of “his appalling behaviour” in getting a staffer pregnant. Midweek, the former deputy prime minister received another damning assessment, although not quite so overt. His actions as agriculture minister, according to the Moss report, contributed in no small way to the disgusting cruelty of the live animal export industry. Philip Moss found that the Department of Agriculture “lacks the skills to ensure the humane treatment of animals in the live export industry”. There was a catastrophic failure to regulate the trade and it was due in part to a culture of fear within the department.

The report found Joyce’s removal of the department’s Animal Welfare Branch in 2013 led to many of the failures identified. Coalition MPs say the issue is still a running sore in their electorates. Labor is promising to phase out the industry, while Joyce’s successor as minister, David Littleproud, is going to appoint an inspector-general of live animal exports and says independent inspectors will be on board ships with cameras. This follows Labor policy but Littleproud says he “doesn’t care who thought of the idea”.

Labor also first thought of the idea of putting asylum seekers in offshore detention centres on Manus Island and Nauru. Five years later it has become a major negative with voters and featured prominently in the Wentworth byelection. Morrison seems to have heard the message and says there are fewer than 50 children and their families left on Nauru and “it’s fallen by 30 in just the last few weeks … and we’ll continue to work progressively on that”.

Senior ministers are quietly briefing that the families brought to Australia for medical treatment will not be sent back. But there was a jarring reaction from Abbott. He told 2GB Nauru was not a “hellhole” and “medical facilities were a lot more extensive than in most Australian regional towns”.

Against the evidence of doctors who work on the island and the recently expelled doctors from Médecins Sans Frontières, Abbott said “they [the children] are being very well looked after on Nauru”. He also claimed, “If you like living in the tropics, it is a very, very pleasant island.”

Morrison agreed the island was being unfairly maligned. He urged respect for the “10,000 Nauruans who live there. That’s their home.” That is because they have chosen to stay and not emigrate elsewhere – a safe choice denied the asylum seekers. This false equivalence does the prime minister no credit. Nor does Abbott’s false statement that most of the detainees are “economic migrants”. The United Nations High Commissioner for Refugees has found differently.

Morrison’s appeasement of both Joyce and Abbott – borne of his own conservative sympathies and the losing hand he has been dealt – will do nothing to save his sinking government.