Malcolm Turnbull is likely to reverse his decision to retire from politics, and stand again in Wentworth this year. Long-time Turnbull associate Christopher Joye yesterday offered an estimate that Turnbull was 60% likely to remain.

Of course, only Turnbull and wife Lucy know what he’ll finally do, and they stayed silent over the weekend.

A Turnbull “Nellie Melba” act might be politically clunky but the case for it is strong purely from a party perspective. The NSW Liberal Party has realised that Wentworth is suddenly a tough proposition without him. Talk of shoe-horning Nick Farr-Jones into the seat suggests how desperate the Liberals are to find a high-profile name to succeed Turnbull.

Neither side of politics is overburdened with cash for this election, and they face state elections in Victoria and NSW over the next 11 months as well.  But the Liberals face a number of tough contests with stretched resources. Having to devote money to just hanging onto Wentworth wasn’t in the game plan a few months back. In metropolitan Sydney, the focus should be on regaining Bennelong, not trying to keep the once blue-ribbon Wentworth in the Liberal column.

The only one who can fix that is Turnbull himself, by standing again — and by deploying his considerable fund-raising capacity in support of the party.  Tony Abbott and Joe Hockey not merely lack Turnbull’s deep business connections, they appear to have gone out of their way to alienate corporate supporters in recent months.

With Turnbull back, the Liberals can cross Wentworth off the list of seats they need to worry about.

But this will all be naturally viewed through the prism of Turnbull’s burning ambition. There’ll be opposition within the ranks of Liberal MPs to a Turnbull reversal, not just from party conservatives, but simply because he is regarded as a priori a destabilising figure. Any Turnbull announcement will immediately be considered for its implications for Tony Abbott’s leadership – not just, or particularly, now, but later in the year.

And that’s all fair enough. Turnbull isn’t about to change his nature, although he did offer to serve under Tony Abbott, which showed a great capacity to get over the events of last November — greater, apparently, than Abbott himself has. But there are other dimensions to his continued presence in Parliament that should be considered.

Turnbull badly damaged his reputation in the Godwin Grech business. Voters tuned in for that, saw that he’d made a truly colossal error of judgement, and reacted accordingly. He was damaged goods after that – perhaps fatally damaged.

But he has, bizarrely, been redeemed by his subsequent defeat. The right-wing putsch by his party’s climate denialists and his assassination at the opportunistic hands of Tony Abbott has come close to wiping the Turnbull slate clean. Voters haven’t forgotten Grech, but they more strongly associate Turnbull now with the idea of sacrificing your career for something you believe in.

Even Kevin Rudd – who didn’t disguise his cold hatred of Turnbull during the faked email affair – said as much.

That means that Turnbull now speaks with more authority on policy issues. His defeat has given him that rare political commodity of credibility – credibility as a bloke who is willing to stick to what he believes in, even at the cost of his job.

Coupled with Turnbull’s brain and wealth, this means his remaining in Parliament will be a direct injection of policy rigour into public life.

Let’s be blunt: Parliament is not overburdened with men and women who can make a serious contribution to high-level public policy debate. There are a few, on both sides. But beyond the Lindsay Tanners and Andrew Robbs, Australia’s intellectual leadership is outside Parliament, in business, in academia, in NGOs, in the bureaucracies.

Even if he didn’t regain the top job, Turnbull can directly influence policy using his brain, his personal wealth and his authority. After all, this is the bloke who shamed Peter Costello into embarking on serious tax cuts with his tax analysis not long after arriving in Parliament.

That was all (correctly) seen through the Turnbull-burns-to-be-PM prism, but it was a pretty useful contribution to public policy from a newly-arrived backbencher.

We should step back from the fixation with Turnbull’s ambition for a moment. If we treasure high-quality policy and value public debate that is rigorous, informed and free of the game-playing of vested interests, having a figure like Turnbull in the game is crucial. The bloke improves public life by being in Parliament, regardless of whether you agree with him on any particular issue.

Turnbull doesn’t have to be Prime Minister to make a huge difference to Australia.