Sussan Ley has blown Malcolm Turnbull's cover. She has resigned not because she concedes any breach of the rules covering politicians' travel or even the Prime Minister's code of ministerial conduct.
On the contrary, she is confident that material she handed to Turnbull's department head on Friday morning would have established her innocence on both fronts.
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Sussan Ley quits
Following days of intense scrutiny over her expense claims, Sussan Ley has resigned as Health Minister with Malcolm Turnbull announcing changes to the MP entitlements system. Courtesy ABC News 24.
No, she has gone before two inquiries pass judgment on her conduct because politics demands her scalp and, in her words, "the team is always more important than the individual".
Our ever pragmatic Prime Minister has accepted her resignation without releasing the conclusion of the inquiry he instigated on Monday for the very same reason.
The longer she remained a cabinet minister, even one stood aside for the duration of the probes, the more likely any excessive behaviour of other ministers would dominate the political agenda and overshadow this weekend's visit to Australia by Japan's Shinzo Abe.
Sensibly, Turnbull has also announced long-overdue reforms to the system governing MPs' expenses, though the key change is not, as he suggests, the introduction of monthly disclosures.
Rather, it is the setting up of a body independent of government to oversee a revamped system.
This is an advance on the 36 recommendations that were made almost a year ago by the review set up after Bronwyn Bishop brought us "Choppergate" but are yet to be implemented.
Turnbull says it is his idea and it's a very good one because it addresses perhaps the biggest weakness in the current system – and the one that probably caused Ley's downfall.
That weakness is that MPs can ring a bureaucrat to seek an assurance that a particular claim is technically within the rules without facing tough questioning.
Had Ley's office been asked some hard questions over her trip to the Gold Coast in May 2015, she surely would have modified the claim to recognise that a slab of the trip became personal when she attended an auction and bought an apartment.
Having responded to the immediate political imperative, Turnbull now faces the conundrum of who to replace her with. Arthur Sinodinos has been acting in the role, but he is in the Senate and has the key role of cabinet secretary.
The imperative is to have a formidable performer to counter Catherine King, one of Labor's stronger performers, on the floor of the lower house and three Victorian men, Josh Frydenberg, Greg Hunt and Dan Tehan, are likely contenders.
But the bold decision would be to put the onus squarely on deputy Liberal leader Julie Bishop to step from the relative comfort of foreign affairs and take on one of the most challenging domestic portfolios and one of the Coalition's biggest areas of vulnerability.