Whoever said or emailed what to whom, David Leyonhjelm’s Adler shotgun blasted through Coalition ranks last week.  What this week’s Spectator Australia editorial calls ‘Adlergate’ has badly damaged Malcolm Turnbull, as his Newspoll approval rating plunged to depths worse than Tony Abbott’s before his ouster.

As Philip Hudson pointed out in the Australian, only one PM has ever recovered to win an election from a satisfaction of less than 30 per cent: John Howard in 2001.  If Turnbull continues his current trajectory, his leadership and the Coalition government are toast.  Indeed, last week’s shemozzle may have marked the point of no return.

Adlergate’s biggest casualty is Turnbull.  But almost as damaged was his vanquished predecessor, Abbott.  Lately, Abbott has been making a deliberate effort to raise his profile, with speeches, media appearances, and his leading the crusade against factionalism and gerrymandering in the NSW Liberal party.  Mostly, these have gone well for him.

Yet Abbott chose to make unnecessary public interventions in the guns-for-votes controversy. First, he tweeted a warning against trading watered-down gun controls for Leyonhjelm’s support for Australian Building and Construction Commission bills, wedging Turnbull from the right as Labor did from the left.  He was even more poorly-advised in then upping the ante to talk Adlergate and leadership on the ABC’s 7.30 programme, denying he or his office did Adler deals with Senator Leyonjhelm in 2015, and saying wistfully of a leadership return ‘It’s not a question of what I might like, it’s a question of what the party room wants’.  No wonder a cornered Turnbull felt driven to bite back so hard against Abbott in parliament the next day.

The last thing Abbott, who has been very careful to do the right thing by the Coalition team, can afford is to be depicted as a Kevin Rudd, actively trying to destroy Turnbull as Turnbull destroyed him.  That, however, is exactly how Abbott’s opponents and detractors painted him last week.  Abbott was reasonably defending his record as PM from impugning by others cravenly covering their political arses, but his interventions were the last things the government needed.

His prospects of leadership redemption have been damaged by last week, and many of his supporters are left disappointed and perplexed by what erupted from nowhere.

Yet with Malcolm becoming Untenable Turnbull, ever less likely to last the distance, Abbott remains the only and, provided he has learned the lessons of what went wrong before, best leadership alternative.

Abbott will only return to the leadership, however, if Liberal MPs and grandees draft him to save the ship.  He will not be brought back if he’s seen as being disruptive or a distraction. Last week will have driven colleagues and power-brokers from his cause, not to it, and has undermined the goodwill that his general support for Mr Turnbull, despite the PM’s shabby treatment of him and keeping him out of Cabinet, has been building.

Consequently, Adlergate shows the time’s come when the Liberals must consider looking beyond Turnbull and Abbott if they want to ensure their survival not only as a government, but as a centre-right political force.  If Turnbull’s leadership becomes untenable there must other alternatives if, for whatever reason, a return to Abbott isn’t possible.

Disregard the likes of Julie Bishop and Scott Morrison.  Bishop, as deputy to three leaders and four leaderships, has played the Vicar of Bray far too long, and Morrison damaged himself badly in the 2015 leadership coup. And neither have proved original thinkers and innovators when it comes to policy leadership that can drive the government to re-election.

So other senior ministers must be ready to step up.  They need to be in the Lower House and have sound political judgment; mainstream centre-right economic and social values; the ability to think for themselves about policy; clean skins when it comes to past plotting and intrigue; and effective public engagement and media skills.

Against these criteria, there are just two current cabinet ministers meeting all of them: social services minister Christian Porter and energy minister Josh Frydenberg.  Porter has been doing very well in making a case for comprehensive but unpopular welfare reform, is media-friendly and was also a state treasurer and attorney-general.  Frydenberg, while not nailing down portfolios for any length of time in his rapid rise under Abbott and Turnbull, has become a favoured fixer of knotty political and policy problems, is proving to be a strong media advocate for the government when doing so is, frankly, a shit sandwich, and conducted himself honourably in September 2015 and since.

Grooming next-gen leaders like Porter and Frydenberg means the Liberals have choices if Turnbull loses the confidence of his party room in the next year or so.  While personally preferring an Abbott restoration in that event, it pains this ‘del-con’ to say Adlergate’s confirmed the necessity of starting to look beyond him to secure the future of strong, sensible centre-right politics against a resurgent, shamelessly populist and profligate Labor party led by union puppet Bill Shorten.

Such is what the incredible, shrinking leadership of Malcolm Turnbull hath wrought.