Yet there is no expectation - even on the part of Opposition parties - that Key will not weather the deluge of criticism that has rained down on him since the report's release on Tuesday.
The Prime Minister's week of absolute, undiluted hell reached its climax in the mind-boggling revelation that he remained in seemingly cordial contact with the very person who has been a root cause of the aggravation he is now enduring - Whale Oil blogger Cameron Slater.
In conversing with Slater - the second most-despised figure in New Zealand politics after Kim Dotcom - Key has compromised his assurance that he had no knowledge of the dirty tricks operation.
The timing of their text conversation - the day before the release of Gwyn's report - was equally foolish in further compromising that assurance.
Key then topped that by misleading Parliament by not fessing up to his text conversation when specifically asked whether there had been any such contact.
Such reckless and consequently self-incriminating behaviour left most observers and voters completely gob-smacked. So gob-smacked that the torrent of criticism raining down on Key went into temporary abeyance.
When it came to trashing his credibility, Key seemed to be doing enough on his own without assistance from outside.
But the absence - so far - of any public backlash against the Prime Minister bar those who already detest him is a source of of intense frustration for Opposition parties. And more so the more Key's memory lapses impede on serious matters of state.
What began with a failure to recall whether he was for or against the 1981 Springbok Tour was followed by forgetfulness over how many Tranz Rail shares he owned.
Then there was the inability to remember how he voted on the drinking age, along with the sudden case of amnesia surrounding the identity of the passengers who flew to New Zealand aboard a mystery CIA jet.
Things started to get even more worrying when Key confessed to being unsure if and when he was briefed on Dotcom by the Government Communications Security Bureau.
They got even more dodgy when Key professed he could not remember whether he had phoned the brother of an old school pal urging him to apply to become the director of the GCSB.
This week's lapse, which resulted in Key having to come down to the House to correct the record, was too much for Winston Peters to swallow.
He asked the salient question of how many more times could someone who was supposed to be the smartest guy that has ever run the country, but who had been caught fair and square telling a porkie, claim to have suffered a "brain-fade" and get away with it?
Take Key's attempted hiding of his conversation with Slater. Key insists he was not specific about that contact when asked because he wanted to make sure his reply was accurate.
That simply does not wash. Key knew full well he would be asked when he had last had contact with Slater because he had been asked the very same question several weeks ago when Opposition MPs started probing Key in Parliament on the revelations contained in Hager's book regarding the smear campaign run by Slater and Jason Ede, one of Key's senior advisers.
That created a splash because Key ducked his opponents' questions through the ruse of saying his contact with Slater had been in his capacity as leader of the National Party rather than Prime Minister. The distinction meant Key was not obliged to detail his discussions with Slater to the House because he was not accountable to Parliament in his capacity as party leader.
Key cannot similarly ignore Gwyn's report because it falls within the bounds of ministerial responsibility. Despite the huge coverage that has ensued, the wider public has remained spectacularly underwhelmed by it all, however.
Political journalists can have enormous fun exposing the large holes in Key's denials. The editorial writers can thunder in fulsome unity. Peters, Labour and the Greens can demand further inquiries and resignations only to be stymied by public inertia. That is why Labour has adopted a more moderate stance.
It is calling for an apology from Key rather than his resignation because it thinks the first option is far more realistic than the second - the preference of the Greens.
Labour's view is that it is extremely difficult to get voters wound up by what Slater and Ede were doing despite it being despicable and very, very wrong,
Key is not going to resign. Calling on him to do so only ends up sounding shrill.
Were he and National on the end of some really bad showings in the opinion polls it would be a very different matter.
Take the example of Jenny Shipley when she was prime minister. She was unpopular and became even more so when she was badly caught out by denials about what was discussed at a dinner with entrepreneur Kevin Roberts.
Shipley made a complete hash of her handling of the affair which only succeeded in confirming voters' negative impression of her.
Key's popularity may conversely make him think he can take liberties that she could not. But the worm can turn. And sometimes before a politician even realises it. Key would be wise to assume he is not exempt.
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