It did not go down well with Tuhoe, who only days before had learned the brutal lesson that timing is also everything in Treaty of Waitangi settlements.
The tribe, already mistrustful of the Crown, was taken by surprise when it had the jewel in the crown of its hoped-for settlement - ownership of the Te Urewera National Park - pulled from its grasp in an apparent last-minute Sunday decision by the Prime Minister.
It had expected to sign the agreement yesterday after two long years of negotiations.
If the decision appalled Tuhoe, it also took the Maori Party by surprise.
It came just one day after Mr Key and Treaty Negotiations Minister Chris Finlayson exhorted members at the party's regional conference to trust them and not be sucked in by attempts to undermine measures for Maori by the likes of New Zealand First's Winston Peters.
Had it been situation normal, National would have been able to get the ownership handover through with little murmuring.
By and large, the wider populace was accustomed to the settlement process bubbling along, and significant steps such as vesting ownership of the volcanic cones in Auckland-based iwi and allowing co-management of the Waikato River have so far resulted in little public reaction.
But the middle year of a parliamentary term is delivery year for support parties. So, in quick succession, the Maori Party wins began to snowball. In February, the Maori flag flew alongside the New Zealand flag for the first time.
Then the Government agreed to the Declaration of Indigenous People's Rights, Whanau Ora became a reality and the Government's proposals to replace the Foreshore and Seabed Act and allow Maori to claim customary title became a talking point. Simultaneously, public attention was again starting to focus on settlements as National stepped up the pace to try to reach its goal of settling them by 2014.
Add in other issues with potential to blow up in the Government's face - mining and a Budget including increases to GST - and the crucible had got red hot. It perhaps didn't help that Mr Key was overseas on a succession of trips while the discomfort was building within his own Cabinet ranks, as well as in National's wider constituency. But by the time he returned, it was clear something had to give.
So Mr Key decided to call for a cup of tea.
The Maori Party's horror was more at the way the Government had dealt with it than at the decision itself. Maori Party co-leader Tariana Turia was appalled by what she saw as an unjustifiable "loss of nerve" and lack of integrity in Mr Key's dealings with Tuhoe.
The timing of the decision makes it clear it was largely a political decision, but it did help that Mr Key had very solid policy grounds to point to in making it.
Transferring as significant a part of the conservation estate as a national park to Tuhoe would have raised expectations of iwi following their settlements, as well as perhaps aggrieving those who had gone before.
It was not a good time to upset the Maori Party. Next week, it will have to support a Budget likely to include an increase in GST; something that is anathema to the party.
But this is also a lesson that it is not always the Maori Party which is the uncomfortable one in the governing arrangement.
A few months into the Government's term, Mr Key pointed out at a post-Cabinet press conference that it was a two-way street and National, too, would have to take some risks for the sake of its Maori Party partner.
The truth of that comment has now become blatantly clear and the Maori Party knows it should not underestimate those risks to National.
Hence Mrs Turia's praise for National's "courage" in backing Whanau Ora - the Maori Party initiative that will see providers funded to deal with whanau in a far less prescriptive manner than now happens. At a philosophical level, Whanau Ora, a diluted form of self-determination for Maori families, fits well with National's philosophy of personal responsibility.
But at a practical level, it is a potential minefield and National knows it.
The foreshore and seabed issue also has the ability to cause problems for National and Mr Finlayson has conceded that, if badly handled, it has the potential to blow up in its face.
So Mrs Turia did not agree with the Tuhoe decision, but she did understand it was causing National significant discomfort which it could not perhaps afford.
Settlement for Tuhoe now seems a long way off, although they hope to begin talks again next week. Mr Key last week acknowledged it could take some time and indicated National could back off from the 2014 goal given the complexity not only of Tuhoe's claim but others such as Ngapuhi's.
Mr Key has emphasised the creative nature of his Government, and treaty settlements themselves have become more creative in the past decade. Tuhoe have already rejected simple co-management, but there are other possibilities.
One example is the Ngati Whare agreement, which gifts a block of forestry land to the iwi to be re-gifted to a trust to which both the iwi and the Crown appoint trustees. It is likely to be variations on such themes the Crown returns to now.
As for the hand-wringing over the Prime Minister's joke about Tuhoe looking to have him for dinner, the most appropriate response was that from Maori Party MP Ururoa Flavell, who suggested it was unwise given the present hurt but added drily "it's probably correct".
- Claire Trevett is a parliamentary reporter for the The New Zealand Herald.
