Illustration: Jim Pavlidis So why not clear this irritant for showing "no leadership", as the leader of the NSW National Party, John Barilaro, urged on Friday when he called for Turnbull's resignation? Here's why. There are four people in the federal Liberal party who are touted as potential replacements. The two with most support are Immigration Minister Peter Dutton and Foreign Affairs Minister Julie Bishop. Dutton is the champion of the party's conservative faction and Bishop of the moderates. What has Peter Dutton been telling the agitated supporters who urge him to challenge Turnbull? "Our best chance is to make the Turnbull government a success," he has been advising colleagues. "We have to get back to work." And when colleagues have sounded out Julie Bishop as a contender, she tells them: "I will never challenge Malcolm." Neither is campaigning or organising for the prime ministership. You can't replace the prime minister unless you have a replacement. There isn't one.

The touted four: Scott Morrison, Tony Abbott, Julie Bishop and Peter Dutton. Credit:Andrew Meares Why the reluctance? They've seen the deep, enduring damage that a leadership coup inflicts. It didn't work for Labor. The cycle of political violence unleashed when Julia Gillard tore down Kevin Rudd, who then tore down Julia Gillard, ended only in political failure and lasting bitterness. The cycle of political violence unleashed when Tony Abbott tore down Malcolm Turnbull, who then tore down Tony Abbott, is heading perilously towards the same outcome. You can't replace the prime minister unless you have a replacement, and right now, there isn't one. Credit:AAP Abbott himself would be only too ready to perpetuate the cycle if opportunity presented. He is the third of the candidates sometimes mentioned as a candidate.

But while the former prime minister is not a spent political force, he is not a serious candidate for the leadership. He enjoys the boisterous backing of some conservative commentators but he lacks the numbers where it counts – among his colleagues. He has frustrated a great many with his serial critiques of the government. He would not improve the party's standing in the electorate. Apart from a handful of his stalwart conservative allies, the Liberals are looking to the next generation of leaders, not the last. If these dismal precedents haven't deterred some plotters, it's made a big impression on the grown-ups in the Liberal Party, Dutton and Bishop among them. They will not challenge and, if urged, will not stand. However, this is not necessarily a permanent state of affairs. Dutton has leadership ambitions. He is being intelligent about advancing them. Most recently he engineered the postal plebiscite on same-sex marriage. It was a piece of lateral thinking that broke a parliamentary impasse and solved a problem for the government. He has worked himself into a position as a trusted adviser to Turnbull and a valued member of the cabinet and the cabinet's National Security Committee. In the next couple of weeks he will assume his new position as Australia's first Home Affairs Minister when his Immigration and Border Protection Department absorbs the Australian Federal Police and ASIO to create a supersized national security agency.

He's not impatient for the leadership and he's realistic enough to see that he is unpopular with the people. He knows that he has to change his image. That will take time. At 47, he has plenty of it. But while he's working for the success of the Turnbull government, he, like all of his colleagues, has thought about the party's options if it can't be salvaged. He's given colleagues the idea that, in the face of inevitable defeat at the next election in the next year to 18 months, he'd hope for a gracious Turnbull resignation. This would open the way to an "easy handover" of the leadership. The last time a prime minister resigned by choice was in 1966 when Robert Menzies decided that, after a total of almost 19 years in power, it was time to retire. So far in Turnbull's prime ministership he's been very ready to dump policies, positions, principles and personnel to hold his position. It's been the only consistent thread running through his term – survival at any cost. He seems an improbable candidate to become the first prime minister in half a century to walk away without a fight. If Turnbull were leading the party over a cliff at the next election and refused to resign, would Dutton strike? That's the judgment he would have to make; people close to him suspect that he would act rather than acquiesce in a government death spiral. He was spotted this week jogging around Parliament House. In Australian Kremlinology this is taken as a sign of leadership ambition.

In either scenario, whether Turnbull were to stand down, or if Dutton decided to turn against a hopeless leader, would Bishop stand by? Would the deputy Liberal leader who's served four leaders over the past 10 years line up to serve yet a fifth leader? Let's be plain. Bishop and Dutton loathe each other. They work professionally together in cabinet but they share a deep mutual animosity. They are both confident, capable people with thick skins and high resilience. They each regard themselves as standard bearers for the Liberal Party. They are at opposite ends of the ideological spectrum, within the Liberal firmament. The prospect of a Dutton takeover is probably the one scenario that would galvanise Bishop into contesting the leadership. Again, people close to Bishop suspect that she would act rather than acquiesce. At 61, Bishop is older than Dutton but she is energised and fit and has no thoughts of slowing down. She was last elected deputy on the same day Turnbull struck down Abbott. The party room gave her 70 votes against her only competitor, Abbott acolyte Kevin Andrews, who won 30.

She's a popular choice among backbenchers looking for campaigning firepower. When voters are asked to choose their preferred Liberal leader, Bishop is sometimes top choice, sometimes second to Turnbull, but she's consistently well ahead of all the others, including Abbott, Dutton and Treasurer Scott Morrison. What about Morrison, the fourth name sometimes canvassed as a leadership contender? He, too, lacks the numbers. He has very modest support among moderates, who consider him a conservative, and not much more among conservatives, who have yet to forgive him for what they consider to be his disloyalty to the Abbott prime ministership. Like Bishop and Dutton, Morrison is also committed to working for the success of the Turnbull prime ministership, and he tells his colleagues so. So when you hear the fevered talk next week of the end of Turnbull, remember this. If you want to replace the prime minister, you have to have a replacement. There isn't one, not yet. If there were a compelling, ready alternative, he or she would have been installed after last year's election when Turnbull led the government to within a single seat of disaster.

"Every week the media tells us the government is finished," Scott Morrison tells colleagues, "and every Monday we're still here". He's right. And that observation has been right for the past year-and-a-half. But a week will come when that is no longer true. Either Turnbull will have recovered and his government will be rampant in the polls, or he'll be dispatched by his colleagues. Which is more likely? When Morrison tries to cheer his demoralised colleagues, he doesn't sketch a brilliant winning Turnbull strategy but tells them: "Don't give up. While there's Shorten, there's hope." Even at the top levels of the government there's hope beyond experience that Turnbull can turn things around. But their more realistic hope is that the government will succeed because Labor will fail. Still, the key leadership contenders are showing more restraint and maturity than we've seen in Labor or Liberal governments in the past decade. Turnbull will be given a new year with another chance. This will be one killing season without a killing.

Peter Hartcher is political editor.