Malcolm Turnbull needs to move quickly — next week, preferably — to take the Liberal leadership and get conservative politics out of this leadership absurdity.

Costello may still intend to linger on the backbench while he gets his post-political affairs in order — thank you taxpayers and the voters of Higgins — and while he remains there, some MPs will harbour fantasies that he can be convinced to take the leadership. Nothing short of a Sherman-style declaration will stop that.

But if the only thing stopping Turnbull from making a move was the concern that Costello would use a contest as his excuse to have a go himself — technically, if Turnbull challenged, Costello could enter the fray without having himself “challenged” — Costello’s declaration that he’s not interested in the job at least temporarily removes that impediment.

It needs to happen fast because even Nelson’s one strength, populism, is deserting him, along with what little luck he has had. The 5c-per-litre excise cut didn’t get him any poll bounce, but at least it made life uncomfortable for the Government, flushed out a leak or two and got the political debate onto an area that Nelson felt comfortable in.

Snobby commentators (like me) deplored his pandering to LCD politics, but it worked. He tried to repeat the trick yesterday with his proposal to raise the single pension level. The timing was, according to Liberal sources, Nelson’s decision alone — the proposal itself had been debated for some time within shadow Cabinet and the leadership group, but it was Nelson’s call to launch it yesterday.

As it turned out, the timing was unfortunate, with the announcement swamped by Costello Craziness. And there’s a good chance the actual introduction of the bill to raise the pension next week will be carried out amidst the febrile atmosphere induced by the book launch. Given the ubiquity of Costello, that would have been hard to avoid, but at least they could’ve checked with Costello to see if he was going to drop any bombshells before going ahead.

And by the way, thanks Pete for that crack about Nelson not being a significant player in the last Government. Talk about damning with faint praise.

The decision to run with a minimalist package that only lifts the single pension rate (with further rises for others to be announced “over the next two years”) was also a misstep, although an understandable one. Pension groups immediately demanded an increase for couples as well, as did the RSL and Carers Australia. That undermined the message — particularly with the constituency the announcement was aimed at — and reinforced the Government line — hastily cobbled together yesterday afternoon — that it was working on getting the issue right for everyone in its tax review.

Perhaps the Opposition was wary of a decision to go large with an increase for everyone due to the huge cost — that’s the price you pay for surrendering some of your economic credibility.

The Government might also reflect on the fact that most aged pensioners are natural Coalition voters — even if Kevin Rudd did unusually well with them last November – and decide that this is one battle they can afford to lose, especially if a big pension increase for everyone will have been in place for over twelve months before the next election.

Costello’s decision to remain on the backbench also won’t help Nelson, however much he has “cleared the air” for his leader. Every interjection from Costello in Parliament, every comment in the media, will be analysed for its significance and compared to Nelson’s performance. We’ve seen how indefatigable Costellogy is, how it can thrive even on total silence.

How soon before Dennis Shanahan — absent from today’s Costello Climax Coverage — starts beating the drum again on his behalf? How soon before Tony Abbott reaffirms his love for Costello? His mere presence is destabilising. Between the book, his parliamentary pension and speaking gigs, surely Costello doesn’t need a paying gig between now and when he picks up a suitable board directorship or two? He should pull the pin. It’s not like the Liberals will lose Higgins.

Turnbull should start making some calls from Europe, where he is holidaying until Sunday. It’s time to move.