Sixteen months ago, Turnbull put forward two good reasons why the Liberal Party should dump Tony Abbott. Abbott didn't have, and wasn't selling, a coherent strategy, particularly on economic matters. And he had seriously alienated voters, with months of opinion polls showing that he had lost voter confidence and was incapable of retrieving it.

Sooner or later, probably sooner, Turnbull (now about 16 months into his premiership) is going to be judged by his party by just the same criteria, as well as for other alleged high crimes and misdemeanours. He has not yet had the span of bad polling data but the trend is clear and there is no strategy for improving his situation. On present polling, Labor would win an election by about 20 seats. One must never underestimate its capacity to lose an election, but it is not obvious how it plans to squander that lead. Or what the Liberals plan to stop it happening.

Meanwhile, Turnbull's "plan" for "jobs and growth" that so underwhelmed electors seven months ago is now manifestly failing to keep Australia ahead of the game in growth, in jobs, or in consumer and investor confidence. Neither the Treasurer, nor the Treasury, nor the economic advisers surrounding Turnbull himself show any great sign of being imbued with a coherent strategy for jobs, growth or emerging issues of housing affordability, let alone of being ahead of the action in dealing with the consequences of decisions made by United States President Donald Trump.

It is conventionally said that governments lose elections, rather than that oppositions win them. In national politics that is not strictly true, at least so far as Labor is concerned, particularly when voters have fresh memories of poor Labor governance. Since the end of World War II, Labor has come from opposition into government only when the party has had positive plans and policies, ones which have been tested in argument and debate. Labor never wins because voters are tired of the Coalition, or because they simply want a change.

Even then, as in 1983 and 2007, the party must appear to have learnt lessons, and to have changed, after substantial defeats. Shorten Labor is still Gillard Labor and has set its face against any reform of its power structures, or against the numbers rorts by which the powerbrokers, including Shorten, maintain control.

There have been times, especially during the last few terms of John Howard, when a Coalition government has seem tired, out of ideas and pretty much out of luck. But voters seemed to prefer the lacklustre and wasted opportunities to the mild blandness and insipidity of a Kim Beazley, or the plain, if exciting riskiness of a Mark Latham.

Moreover, since the end of World War 1, no Labor prime minister elected from opposition was a member of the previous Labor government. If Shorten, a minister in the Rudd, Gillard and Rudd governments, is to be the next Labor prime minister, he would be the first such for 100 years.

It is not yet so clear that voters have positively committed themselves to a new Labor government. But that does increasingly seem the default option to which voters are resigned. It is perfectly true that the present Parliament is only half-way through its first year, with no election required until late 2019, and that governments, typically, make unpopular decisions early in the term in the hope that the benefits of any sacrifices, or unpopular decisions, will be apparent by the time of the next election.

What's not clear, however, is that Turnbull is pursuing any particular strategy designed as an investment either in a booming 2019 economy, or some other actions or omissions that will eventually make the government popular.

Nor is there much in the way of evidence that any of his general or specific criticisms of Bill Shorten and the Labor Party are striking any chord with voters. Some of his critique, like his tantrum on election night seven months ago, are particularly unconvincing. Turnbull has again let Christmas and January escape with an array of minor scandals and embarrassments, and the loss of one of his few able ministers, but without once sharing with the Australian public any sort of story of what the government is doing, or why. There is nothing for his supporters to get on board with.

He has done nothing to allay concerns about an uncertain defence, economic and political situation in relation to Trump's ascension in the United States, or China's reaction to conscious provocations from the new Trump administration. He has been less than straightforward with voters and commentators about the impact on Australia, or on any sort of Pacific trading bloc (with or without China, but presumably without the US). His attacks on Shorten for alleged gutlessness and opportunism on that subject may have a germ of truth, but have been flimsy and feeble, appearing rather more to seek political advantage than to demonstrate that he is on top of, or in command of events. Turnbull is better playing statesman than partisan, but now, rather than seeming above the fray appears unsure of which lower leg to bite.

His failure to staunch the government's self-inflicted bleeding over the appalling political and bureaucratic mismanagement of the robo-debt disaster has seemed all too typical of a want of strength, confidence and political common sense. These are just the qualities he once seemed to encapsulate. They also seemed to suggest either that his own department, and his own political office, is not up to the task, or that the leader lacks the courage or capacity to follow his generals.

Tony Abbott was, first and foremost, a political bed-wetter because of hyperactivity coupled with bad ideas. With Turnbull, it is not bad ideas but a seeming want of ideas, ideals, or strategies at all. There is not feverish foolish activity but apparent paralysis of will.

I have observed 11 prime ministers at reasonably close quarters over 50 years. Turnbull, who had seemed to show such promise, because he had fearlessness, his own mind and his own will is now down there with Billy McMahon as, so far, the weakest and most indecisive, a seat-warmer who was unable to galvanise minds, to have lasting memorials or to make history. But McMahon at least had a certain rat cunning and survival instinct. If Turnbull continues in his present style it seems likely that he will have been deposed by his own party, or rejected by the electorate, before he has made his mark on anything. His biggest achievement so far, apart from destroying public hopes for a 21st century broadband system, is to commandeer some meaningless phrases about innovation and agility for his senior public servants to parrot.

One might think that the end of the holidays would provide the Prime Minister with some space, some pulpit, or some occasion with which he could strike out in new directions, and walking away from the nightmare (for him) of 2016. But if this is what he and his advisers are planning, there is little evidence of speeches being prepared, announcements being readied, legislative agendas being cooked up. There is little in evidence of work for the reconvened Parliament, and almost no evidence that he and his Treasurer have gone any distance in getting Senate assent for still programmed budget cuts to health and education. A study of his media statements, announcements and off-the-cuff responses to events does not suggest any fashioning of a narrative, or even an effective line of attack on Shorten.

This time two years ago, Abbott went beyond routine pyromania and attention-seeking self-harm to forfeiting the confidence of the Liberal Party backbench. The knighthood for the Duke of Edinburgh was the last straw to anxious politicians who had come to lose all confidence in his judgment. Abbott begged for another chance to show that he could reform; most of the Liberal caucus had no confidence that he could change but shrunk from assassinating another leader after only 16 months in government, particularly after the debacles of the falls of Kevin Rudd and Julia Gillard. Turnbull, as a minister bound to support Abbott was to be the beneficiary when, little more than six months later, it was clear that Abbott could not retrieve the party's fortunes.

Turnbull has now been Prime Minister for about as long as Abbott was when he received what he described as his near-death experience and announced that "good government starts today". Turnbull, on form, deserves much the same warning, but seems unlikely to get it, if only because there is no obvious challenger, whether from the party's left or right, and certainly no challenger that the public would be likely to get excited about. Yet party hardheads must be in despair at the woodenness of Turnbull's performance, and at evidence of fast-declining public enthusiasm for him. It would, obviously, be a public relations disaster for the Liberals were they to kill off another leader in so short a time. But how long can one follow a leader seeming to sleepwalk towards a cliff?

Put another way, would Bill Shorten and the Labor campaign team prefer to be facing Malcolm Turnbull, and his brains trust (with or without Turnbull's own campaign contributions) at the next election? Or would they benefit more from the chaos and turmoil of yet another coup, and further evidence of Coalition disunity, and an even more charisma-challenged leader – a Peter Dutton, say, or a Julie Bishop? Sixteen months ago, it seemed obvious that Shorten would defeat prime minister Abbott, but, on Turnbull's ascension, it seemed impossible that Turnbull could lose. Against the odds, Turnbull's own inept political management, strategy and tactics took him to the brink of defeat, but Shorten, and Chris Bowen, his shadow treasurer, did a good deal to reassure voters that Labor was able, if perhaps not completely ready, to govern. That's an impression which can only have strengthened as a result of Turnbull's faltering performance since July.

But if Shorten has shown some resilience and self-discipline, he retains all of the weaknesses that prompt many would-be Labor voters to despair. He is a ruthless factional player and former union hack, with an unattractive (and shameful) record of putting his own political interests ahead of working-class Australians. There is no consistent moral or political theme, apart from opportunism and ambition, that can describe the range of political stances and alliances – and betrayals – that have marked his political career. He is not trusted, or even liked, by most of his colleagues, even as Labor has been remarkably disciplined and united in following him. He has never seemed more bogus than when he, with his record, invokes traditional Labor themes, or campaigns on matters such as health, or education.

He leads a party which, as one Labor thinker commented recently, is rejected as a first preference choice by two-thirds of the electorate. It speaks volumes for Turnbull's non-performance that a transfer of power seems more likely than not.

Jack Waterford is a former Canberra Times editor.