His ministers have been quick to learn. One of the prime exponents of the art of ducking responsibility has been Murray McCully. A botched "reform" of the Ministry of Foreign Affairs? Nothing to do with the minister but the chief executive, John Allen, was moved on. The Saudi sheep scandal? It was the lawyers who gave bad legal advice and landed him in it.
Perhaps the most extreme example of the genre, however, is the Prime Minister's current attempt to distance himself from the IRD's inexplicable decision to abandon their planned inquiry into the damage to New Zealand's reputation that could result from our disreputable activities as a tax haven.
In this instance, the fall guys are the Prime Minister's personal lawyer and one of John Key's junior ministers. The cover story requires the lawyer, Ken Whitney, to plead guilty to misrepresenting the Prime Minister, and the junior minister, Todd McClay, to profess to feel "insulted" by any thought that he might have allowed himself to be influenced by the Prime Minister's known support for the foreign trust industry.
The Prime Minister himself, of course, claims to have been totally unaware of the IRD's concerns, and to have pleaded ignorance of it when approached by his lawyer - someone he knew to be a leading figure in the foreign trust business and indeed to be the chair of the Antipodes Trust Group, a major player in the industry.
The Prime Minister's own view of such matters is now well-known, though it is worth recalling that no one would have known anything about those views and his connections to the industry if it had not been for the leak of the Panama Papers. Even after that leak, the Prime Minister was still happy to express strong support for secret foreign trusts as a worthwhile business - indeed, he expressed the hope that New Zealand could become the "Switzerland of the South", a haven where the rich could hide their money in secret.
When Ken Whitney became alarmed at reports that the IRD was preparing to launch an inquiry and approached him on the matter, neither party would have been in any doubt, in other words, as to where they both stood. The approach was in essence a request that the Prime Minister should intervene in a matter of concern to them both and that the IRD should be told to drop its proposed inquiry.
John Key has - improbably enough - tried to equate this request to those many instances when he is no doubt buttonholed for a moment or two by strangers about matters of little consequence.
We are asked to pile improbability on top of improbability by believing that Ken Whitney would then, at the Prime Minister's direction, repeat his concerns to a newly appointed and anxious-to-please junior minister and that neither of them would have thought to mention John Key's known views or to take them into account.
READ MORE: Bryan Gould: Govt serving interests of the rich
What we do know is that the Whitney/McClay meeting was organised almost immediately following the approach to the Prime Minister and that the IRD subsequently, and without explanation, abandoned its plans for an inquiry into foreign trusts.
The end result is that, instead of an independent inquiry organised by the IRD in the public interest into business practices that do New Zealand no credit, we have a limited inquiry conducted by a single finance industry insider, hand-picked by a Prime Minister whose hand has been forced.
When the establishment of that inquiry was announced, it was met with widespread scepticism. With all that has happened since, both the credibility of the inquiry and the Prime Minister's reputation have suffered further damage. We need something better.
Bryan Gould is a former UK Labour MP and former vice-chancellor of Waikato University.
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