When pressed by inquisitors, he's been determined and grim-faced. In countless interviews since things turned sour for him early in 2016, most recently in discussion with Laurie Oakes last Sunday night on 60 Minutes, he's been stoic and defiant when confronted with mounting criticism and negative public opinion polls.

He's refused many invitations to engage with questions such as "What has gone wrong?" and "Why has your personal popularity fallen so drastically from the heights of September 2015?". He's refused to "bite" even when interviewers have offered commonly held explanations, such as disappointing moderates by being too conservative while disappointing conservatives for not being conservative enough.

Instead, Turnbull has consistently argued that "it is not about me" but about the government's performance and plans. He did that again last Sunday. He insisted on talking about policies.

That stoic stance hasn't worked so far. It rarely does when a political leader is under pressure. It didn't work for Tony Abbott or Julia Gillard as they spiralled downwards.

Turnbull should try something different or he may sink further. It is about him. He has a choice between remaining a sitting duck or switching to a new game plan. He can't continue to pretend that the turmoil surrounding him doesn't exist.

Australians are not fools. Nor are political commentators. They know Turnbull is stuck on the horns of a dilemma. He is a liberal in a liberal-conservative party which, partly because it is in coalition with the conservative Nationals, tilts noticeably to the conservative side. The recently departed Senator Cory Bernardi might not believe it's conservative enough but, to most Australians, the government looks conservative on refugees and asylum seekers, action on climate change, same-sex marriage and constitutional change, to name just a few issues.

Turnbull is what he is. He can't change his core beliefs or ideological stances. But strategy, tactics and communication are a different matter. They should be flexible. To survive, he must accept advice and develop a new approach. To use a sporting analogy, he must adopt a brave new game plan. Like sports coaches, that's what political leaders who are lagging do if they are ultimately to emerge as victors.

First, Turnbull should be more open with the electorate in general and interviewers in particular about the internal workings and ideological composition of the Liberal Party and the Coalition. Even his own NSW Liberals laughed at him last year when he tried to pretend, before its state conference, there were no factions in the party.

Having done that, he should be more open about where he stands within his party. Previous Liberal prime ministers, like John Howard, have declared they are proudly conservative. Turnbull should be loud and proud about being a liberal.

He does that at the moment but only on an issue-by-issue basis rather than comprehensively. He's willing to say he personally supports same-sex marriage and a free vote in Parliament while his government supports a plebiscite approach. His situation is somewhat like the NSW Women's Minister, Tanya Davies, who says she is personally pro-life and anti-abortion but doesn't intend to change government policy.

Such a position contains a hard message for Turnbull to sell to both the left and the right in the community. Neither fully trust his instincts. Turnbull should draw with a bigger brush and declare unequivocally that he is primarily a liberal and not a conservative. That may not settle the matter, but it would at least clear the air somewhat. After all, the Liberals are a broad church in which individual conscience is respected.

Second, Turnbull must enthusiastically defend the role of the moderate centre in politics and the need for compromise in government. This is never easy, and is particularly difficult in this era of Brexit and Donald Trump. Moderation can seem like a colourless value, especially if it's accompanied by a bland style. Turnbull must also defend the idea of a balanced approach to policy making. His message should be: "I know that I can't have all that I personally want but neither can my opponents within the party and the Coalition government. 'Winner takes all' will not prevail within my government."

Third, in line with his liberalism and his commitment to the centrist element in the centre-right party, he must pick and choose between the various social issues on the public agenda and take one big stand. The list usually includes same-sex marriage, climate change, and refugees and asylum seekers. He should say to his government colleagues and the public: "This is where I stand. I am going to use the authority of my office to pursue at least one liberal position, though I understand in the spirit of compromise that I can't have it all."

Plenty of roadblocks will be put in his way, including the Coalition agreement and the government policies taken to the last election.

There's no guarantee of success. His conservative party-room colleagues may say: "Right, we've lost patience. You're out now. Let's bring back Tony."

The electorate may say: "Sorry. Too little too late. You've had your chance. We'll vote you out at the first opportunity."

Either way, if he doesn't survive, at least he'll have tried something bold and different.

John Warhurst is an emeritus professor of political science at the Australian National University. john.warhurst@anu.edu.au