It's like the voters' minds are closed off, made up.

Were an alternative Liberal leader waiting in the wings, this intractability would itself be enough to dethrone Malcolm Turnbull.

Indeed, it was Tony Abbott's inability to move the needle which Turnbull cited to chilling effect in his now infamous "30-Newspolls" challenge in September 2015.

But no such personality exists.

Hence coalitionists cling to the preferred prime minister rating because, frankly, it's all they've got. But is it?

Turnbull remains the choice of voters, leading Bill Shorten, by a long chalk. Getting longer.

Shorten, who they've been targeting recently, had been closing the gap and was within 12 or so in previous surveys: 33-45 in March and 35-47 in May. But now, it's out to 31-48 currently.

Yet despite a concomitant improvement in the PM's standing, the Coalition's primary vote is stuck in the mid-30s - a subterranean number that includes the Nationals.

This constitutes a 3.4 per cent swing since July 2016, which, let's not forget, was a colossal stuff-up of Turnbull's unique design (and funding).

Still amid all this gloom for conservatives, this poll points the way forward.

Message number one is this: it's the economy, stupid.

The Coalition remains the preferred manager of the economy, and Scott Morrison, a Treasurer less visible than some, is regarded as effective.

Allied to this is that nearly six in 10 voters prefer Turnbull's stewardship of the economy over Abbott's. No great surprise, but a positive nonetheless.

This leads seamlessly to the other lesson.

Turnbull remains the Coalition's best asset. Without him, the vote might be even lower. Unlike Abbott, even disappointed voters probably don't hate him. Many want to like him.

So where does this lead? Assuming Turnbull is prepared to alter course and campaign strongly on marriage equality, and assuming his deputy survives the looming High Court challenge, Turnbull may have a path to recovery in 2018.

But his party room must give him the space to do it. So far that latitude has been absent. And Turnbull has lacked the courage to demand it. The big test is the clean energy target.

Turnbull needs a proper carbon abatement policy, rather than a political fix transparently designed to appease recalcitrants. That means staring down the Nats, staring down the right, staring down coal.