The other day, I went to a boozy barbecue near Sydney’s northern beaches. The guests were all political mates of mine and we chatted about those insurgent populists who threaten to upend established conservative parties across the globe: Donald Trump, Marine Le Pen, Geert Wilders, Beppe Grillo and, of course, Pauline Hanson — Australia’s version of all four. We put our wide-ranging discussion about domestic politics in an international context. But it was not until the next morning that I realised that we had not even talked about Malcolm Turnbull: he’s our fourth prime minister in four years, who was famous in the UK in the 1980s as the defence lawyer in the Spycatcher case.

In my hungover state, I texted my friends and asked them if they noticed anything odd about the night before. No one even brought up Turnbull. My BBQ buddies are no focus group: we’re just a bunch of conservative journalists, academics and businessmen, who usually vote for the centre-right Liberal party (where the word ‘liberal’ still means more or less what it meant in the 19th century). Still, it’s hard not to conclude that Turnbull, like another Tory ‘moderniser’, David Cameron, is passé. He is the moment that has passed into history.

It was not supposed to be like this. When Turnbull backstabbed his predecessor Tony Abbott in a Liberal party coup 18 months ago, the media herd declared ‘hallelujah!’ The 62-year-old climate enthusiast and former merchant banker, we were told, would transform Australia into a beacon of progressiveness. At the time, I remember attending one of those swanky dinner parties in metropolitan Melbourne where eyes lit up at the mere mention of Malcolm. There was a real sense of excitement. In an echo of Harold Macmillan’s famous declaration that Brits had ‘never had it so good’, Turnbull declared: ‘There’s never been a more exciting time to be an Australian.’ But the trouble for any politician exciting high expectations is that they can almost never be fulfilled. Once he was the ‘it’ man; everyone wanted to know Malcolm or be seen with him, especially in his posh Sydney electoral district, Wentworth (our equivalent of Notting Hill in west London). These days, if you were at the pub and saw Turnbull waltzing in, you’d look the other way, hoping not to catch his eye.

I’ve known Turnbull since 2006, when he was a rising star in John Howard’s government. Back then, my wife Sarah was his press secretary, and it is fair to say we all got on reasonably well. In my experience, he can discourse on anything from demography and Sino-American relations to classical history and the Jewish diaspora. He is also a decent chap. Malcolm and his wife, Lucy, have turned their harbourside mansion into a very pleasant and lovely place. I am among many writers who have been dinner guests there. However, as can be the case with genuinely decent people, Turnbull has not been very effective at his job. Contradicting himself almost every week, he has stood fast in indecision. He has been consistently indecisive.

In the political-loser stakes, Turnbull has form. As the leading republican activist in 1999, he failed to win the referendum to ditch the monarchy, even though polls had supported constitutional change. When he was opposition leader a decade later, in 2009, ordinary Australians shrugged their shoulders with a profound lack of interest. Last winter, as the newly installed PM, he opted for a laggard election campaign that just drove about a million conservatives away from the party of Robert Menzies. We are only in March, but already his government has lost a prominent senator, who has created his own break-away conservative party, and there is talk of other lawmakers defecting to fringe right-wing groups. Meanwhile, the end of the mining boom means higher deficits as far as the eye can see. Labor — a party that barely registered a pulse a few years ago — is leading the government by as much as ten points. As a result, authority is draining away from Turnbull as if from an open wound.

The spectre of Pauline Hanson’s One Nation has returned to haunt Australian politics. Two decades ago, the former fish-and-chip shop owner shocked the nation with her parliamentary maiden address complaining about the alleged dangers of Asian immigrants. She was immediately given the pariah treatment. But now she is back, her party controlling the balance of power in the parliament’s upper house.

My BBQ mates and I are not really enamoured by Hanson, whom I’ve never met. But we understand why she attracts many folks, from Queensland to Western Australia, who deplore both major parties. Above all else, her resurgence represents a backlash against political correctness and identity politics. For instance, our leaders, bureaucracies and public broadcasters have long played down the problems posed by radical elements within Islamic communities, whereas many ordinary Australians recognise that a significant group of Muslims is much more resistant to integration into western society than other ethnic or religious groups. For now, Hanson is filling a void. As a result, she doles out the red meat to hungry conservatives who are turning away from Turnbull in droves.