No one was accusing McCully of accepting a bribe. He was deemed to have offered one.
Hush money, in short, to get a Saudi Arabian businessman to stop using his influence to block a free-trade agreement in return for compensation for losses he incurred as a result of New Zealand suddenly banning live sheep exports more than a decade ago.
McCully could well argue that such a deal was good public policy conducted in the national interest. After all, had not some of his colleagues displayed similar flexibility when circumstances have called for dipping into the public purse?
The precedents included cash on the table when Warner Bros came marching into town demanding not only bigger tax concessions, but law changes as well to keep those uppity trade unionists in their burrows.
All in return for filming The Hobbit in New Zealand.
Had not Bill English handed $30 million to the owners of the Tiwai Point aluminium smelter to keep it running until 2017?
The big differences is that McCully kept his largess secret. There was no publicity.
Had he been upfront, McCully would not be under the hammer now had payments of upwards of $10 million to Saudi businessman Hamood Al Ali Khalaf been made public when the deal was struck back in 2013.
That raises questions about what else has been kept out of the public domain.
McCully has argued the settlement with Al Khalaf was necessary to avoid a claim for damages of up to $30 million. But the minister later admitted the question of damages was not a pre-eminent factor in negotiations,
Despite these inconsistencies, the Saudi sheep saga does not contain enough of the required ingredients to qualify for the title of "scandal."
Neither is the flow of fresh revelations strong enough to keep this political mess in the headlines for very much longer.
The Opposition has been nibbling at the edges of McCully's credibility. It has not landed the kind of king hit which has National reeling.
The affair has lingered longer than expected, however; a bad smell which has disturbed National's otherwise happy post-Budget equilibrium.
Whether the public has taken much notice of the ins and outs and rights or wrongs of the matter - or can even be bothered to do so - is very much a moot point.
The danger for National is that the deal which saw the Government fork out money to foreign interests re-ignites issues where National is in a minority, such as foreign investment and immigration levels.
You would be hard pressed to find as mixture of characters and factors on National's side of the argument more likely to provoke an outbreak of jingoism on the back of anti-foreigner sentiment in turn provoked by having to genuflect to the despots of Saudi Arabia.
You would be hard pressed to find a cast of characters as politically unattractive as those appearing on National's side of the argument.
The list is headed by McCully, someone in whom the public would invest precious little trust. Add to that public prejudice against wealthy Arabs.
Then there is the mind-boggling notion of 900 sheep flying Singapore Airlines to their new home in the heat of the Saudi Arabian desert.
Then there is the icing on this very mixed cake - the redoubtable former National Party president Michelle Boag in her capacity as director of the Middle East Business Council.
Boag mounted a strong defence of McCully on last weekend's Q+A, but will not have changed people's view of him.
McCully is not beyond political redemption. He remains one of National's more effective ministers. But you would not know it.
He has yet to carry the demeanour of wisdom and worldliness that wraps its way around the shoulders of long-serving foreign ministers - yes, even Winston Peters.
Because they spend so much of their time out of the country, long-serving foreign ministers become spectators of domestic politics rather than participants in the heated day-to-day politics. They develop perspective. They may even have the whiff of neutrality about them.
Such a metamorphosis has so far eluded McCully, whose public image remains predominantly that of a back-room "fixer" and the power behind the throne of successive National Party leaders. It is an image that voters find cold and flinty.
With the media relentlessly reinforcing this perception, McCully has fatefully and probably permanently been cast as the symbol of what people do not like about National.
McCully is further handicapped by an apparent blind-spot which, despite his capacity to clear up a political mess which is the fault of others, sees him only making more of a mess - the case with the latest firestorm to strike his portfolio.
McCully is a very hands-on minister who is suddenly very hands-off when there is trouble, such as with the case of the Malaysian diplomat who was allowed to leave New Zealand during an investigation on sex charges.
Then there was the extraordinary revolt by diplomats in the face of a crude restructuring of the Ministry of Foreign Affairs which McCully had instigated but later fled from.
Before that was the equally calamitous mistake to appoint a non-diplomat as the ministry's chief executive.
McCully is currently out of the country working on his No1 priority - ensuring New Zealand's stint on the United Nations Security Council is meaningful and productive.
In his absence, National has gone on the offensive. On Wednesday the Prime Minister taunted Labour with the suggestion that he had Cabinet papers in his possession which would prove to be highly embarrassing for the Opposition party.
Labour is baffled. It can find nothing from its time in government relating to live sheep exports to justify Key's cockiness.
But Key sounded very sure of himself. They cannot both be right. There has to be a loser.
