Turnbull's stratospheric approval ratings have fallen back to earth – as they were always going to – and after scraping home with a one-seat majority in July, the Coalition now trails Labor in published opinion polls and the Prime Minister looks like a man boxed into a political corner.

There are striking similarities with Julia Gillard's position at the end of 2010 – a deal-making prime minister with razor-thin control over the lower house, a rampant opposition leader riding a populist wave of discontent with politics, regular outbreaks of party disunity, an unhappy predecessor lurking in the background and a range of policy positions being adopted that don't always fit with the leader's own preferred position on issues.

Gillard faced a vile strain of sexism that Turnbull has not had to confront. But those undermining Gillard in her own party, mostly, didn't put their names to the attack and hovered in the shadows.

If anything, for Turnbull the disunity is worse: barely a week passes where a member of his own side doesn't attack the Coalition, on the record, putting the PM on the back foot. (Even more amazing: somehow, the government didn't seem to anticipate the recent rebellion over a review of climate policy that was supposed to examine an emissions intensity scheme; the speed of the backdown underscored the lack of political judgement on the issue).

But Turnbull can't blame disunity for all his woes. He has made plenty of his own missteps and blunders. Here are the five biggest:

The first mistake Turnbull made in 2016 was, after setting the hares racing on tax reform and placing everything on the table, deciding to rule out a hike in the GST.

While the government argues it did not abandon the cause of tax reform, and highlights its (largely good) superannuation changes as proof, does anyone actually think that $3 billion net improvement to the budget bottom line constitutes big-bang tax reform?

Pull the other one, Malcolm.

Turnbull had a tremendous amount of political capital to spend when he took the leadership; voters trusted him, they understand the federal budget is in deficit and that paying for things like hospitals and schools costs actual money.

Sure, Labor was readying a scare campaign; yes, state premiers had plans to spend the extra revenue six times over and, sure, the selective advice from Treasury released showed the growth dividend was not as high as the government wanted, to justify raising the rate or broadening the base.

But Turnbull squibbed it and, effectively, spent his political capital on nothing much instead, lost a swag of seats anyway and left people wondering why the PM backed down, and what he stood.

And Australia still needs to fix its tax system and find more money for schools and hospitals.

That leads to point 2...

Initially, Turnbull and co's clever maneuvering to call on the DD made the prime minister look decisive and on the front foot; sadly, by the eighth week of the campaign, and the PM's 4 millionth repetition of his soporific "jobs and growth" mantra, most of the nation had fallen asleep and "decisive Malcolm" had morphed into "that bloke who keeps appearing at shopping centres and looking awkard".

Government types argue that they have a majority, actually, and a Senate that is easier to deal with than the last one. Both of these points are true, and the government has passed some significant legislation in the spring sittings.

But that is the wrong yardstick. If Turnbull had gone to the polls in November 2015 or February 2016, for example, every published poll indicated he would have thumped Bill Shorten.

Even if he had gone to the polls promising a GST hike, he would have had a very good chance of winning – voters reward political courage. And frankly, short of an actual loss, could the result of have been any worse for Turnbull?

Yes, Labor's scare campaign was horribly overcooked – but after four and a bit years of Tony Abbott's opposition ($100 lamb roasts anyone? Farewell Whyalla? Budget emergency?) the Coalition has no right to complain about political hyperbole.

Turnbull's late appearance and subsequent rant about voters being conned was entirely ungracious and ignored vanquished colleagues. Months later, Turnbull was still complaining at end-of-year Christmas parties about those dodgy Medicare text messages. Get over it, Malcolm.

This was an entirely self-inflicted wound. All the PM had to tell the ABC's Fran Kelly was that there would be no change to classification of the rapid fire shotgun until all the states agreed; instead, he waffled, Abbott saw the door ajar and picked a fight, the Nationals got their backs up and the government's political agenda was on hold for a week. Labor could hardly believe its luck.

Time and again, Turnbull's government has given in to the demands of conservative forces on its right flank – the superannuation compromise, the decision to hold an inquiry in section 18C of the Racial Discrimination Act, on the climate policy and most significantly, by dumping changes to the GST (backbench pressure played a major role, despite what the PM claims).

Even when the outcome is actually good – such as the 18C inquiry – the impression is that Turnbull is being led, rather than leading, on issue after issue. In seeking to hold together the broad church that is the Coalition, and learn the lessons of 2009, he has arguably gone too far – and the "Real Malcolm" has disappeared.

But it's not all bad news for Turnbull. There's plenty he can do to ensure he has a better year in 2017 – and maybe, just maybe, get his government back on track.

Pick a fight with Cory Bernardi, George Christensen and other conservatives in the Coalition and call their bluff. The issue to fight on, be it same-sex marriage, climate change, tax reform – is almost secondary. Turnbull needs to demonstrate to voters that centrist Malcolm still exists and fight on an issue that proves it because at the moment, he caves time and again. Increasingly beige Malcolm is enduring death by a thousand cuts. (Don't believe me? Remember that climate policy backflip that took just 36 hours and ignored all expert advice? From a guy who once staked – and lost – his political leadership over climate policy).

The government's policy agenda for 2017 looks, to put it kindly, a little light on. Turnbull needs to advance a big idea. Fixed four-year terms would introduce stability and certainty to electoral politics. Proposing an actual solution to the stand-off over health and education funding would be a good option, too. And what about some new infrastructure projects, rather than just claiming the 2014-15 budget spent $50 billion on projects, when it actually just rebadged a stack of ancient Rudd, Gillard and even Howard era projects and spent about $5 billion of new money. And start talking – in a meaningful way – about why indigenous Australians must be recognised in our constitution.

Sure, most Australians are fascinated by international tax rates comparisons (cough) and yes, despite what Labor claims, this is actually good policy – but arguing for handing the four big banks an extra $7 billion is not – repeat, NOT – a political winner. Turnbull and his team need to strike a deal for companies turning over no more than $50 million and move on.

Sure, the opposition leader may not be the most amazing orator or accomplished opponent in question time, but he leads a united Labor party (and has done for three years. Which is obviously some kind of record), has a deft political touch, an excellent office and has set out a couple of bold policy ideas (negative gearing reform, for example). There are signs the government is trying to reframe Shorten in voters' eyes – Peter Dutton, take a bow – but it's not before time.

The man has served as prime minister, opposition leader, health minister, workplace minister, on the ERC and the NSC, is a deep thinker on policy issues when he wants to be and is arguably the best communicator in the entire Parliament with a devastating ability to deliver a cut-through line (something the government sorely lacks). Keeping Abbott out looks churlish and insecure. A prime minister confident of his own position, on the other hand, would avail himself of all the talent at his disposal. But don't hold you breath on this one.

James Massola is chief political reporter. Peter Hartcher is on leave.

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