There’s been a lot of doomsday talk following the departure of conservative poster boy Cory Bernardi from the Liberal Party last week. According to the missives delivered through the conservative media, Bernardi’s defection either heralds the end of conservatism as we know it and/or the end of the troubled reign of Malcolm Turnbull.

Media groupthink has set in with unsettling speed, making it accepted wisdom that the fracturing of the right can only be a bad thing for the Prime Minister. The only way to stop more voters from abandoning the Liberal Party, according to conservatives, is for Turnbull to capitulate even further to the nostalgic preoccupations of “the base”.

Turnbull’s already acceded to the party’s right wing and conservative supporters on marriage equality, Safe Schools, superannuation reform and climate action.

So it’s difficult to see what else the PM could do to satisfy that demand, short of rolling up his sleeves and single-handedly building a coal-fired power station, or throwing copies of the Racial Discrimination Act onto a bonfire.

[Feral Bernardi makes Turnbull’s rotten 2017 a lot worse]

And as a number of columnists and commentators noted in the past week, even when Turnbull makes such concessions, the right don’t credit him with doing so because he’s not a “genuine” conservative and apparently his heart isn’t in it.

This preoccupation with dragging votes back from the right (perhaps deliberately) ignores another way that Turnbull could increase the Liberals’ primary vote. That’s by moving back to the centre and taking votes from Labor.

Conservatives love to quote John Howard saying the Liberal Party is a broad church to justify the importance of keeping outliers such as Bernardi and the LNP’s George Christensen in the tent. In reality, they’re more interested in the possibility of a conservative making another tilt for the leadership and want to hold on to every potential party room vote.

But another Howard axiom has even more relevance: elections are won and lost in the centre. So perhaps it’s time for Turnbull to bring on a Liberal Party renaissance by taking it back to the centre.

Yes, Turnbull has all but abandoned the moderate supporters of the party by trashing his promise to return the Liberal Party the centrist style of Menzies. But by re-invoking that promise, the PM could make amends.

And a quick perusal of opinion polls suggests there is still a strong proportion of moderates within the Liberal voter cohort. Some 38% of Liberal voters oppose Australia having a ban on Muslims entering the country; 57% think it would be good for the economy to make multinationals pay more tax; 41% support a republic; and 66% support voluntary euthanasia.

[Poll Bludger: the electoral reality of Bernardi’s ‘silent majority’]

Of course, Liberal and LNP conservatives would have a meltdown if Turnbull responded to Bernardi’s departure by shifting to the centre. Yes, they would threaten to leave, and now thanks to Bernardi they have somewhere to go, particularly if they are true Liberals with a free market bent rather than Hanson-lite protectionists.

But this would benefit Turnbull. Having the arch conservatives outside the Liberal tent would give the government flexibility to negotiate the passage of economic reforms through the Senate with Bernardi, David Leyonhjelm and Family First, while securing progressive reforms with Labor or the Greens.

Even in the House of Representatives, Turnbull has options. If Christensen defected to One Nation, the PM would need only one of the three independents in the lower chamber to maintain a working majority. Both Bob Katter and Cathy McGowan have offered to support a minor Turnbull government on supply and confidence.

An early opportunity for the PM to initiate this shift is the most recently reported move by Liberal progressives to push for a free vote on marriage equality.

According to the report, “new polling suggests 71% of people would look more favourably on the Turnbull government if it allowed a free vote on same-sex marriage instead of holding a plebiscite, including 64% who lean to voting Liberal”.

The moderates have also introduced a new line of defence against Tony Abbott’s insistence that the plebiscite remains Liberal Party policy, claiming Abbott “acknowledged while he was prime minister that the last parliament — the 44th parliament — was the final time when government MPs could be bound.”

Turnbull could arrest his government’s fast-diminishing primary vote by identifying and seizing the best way of bringing voters back to the fold. A clear-sighted view of his options suggests a jump to the left could reap even more electoral benefits than a step to the right.