Tonight's "co-operation agreement" between the Labour Government and the Green Party is a masterstroke by the Prime Minister.
Agreed to by a reported 85 per cent of Green Party delegates, it radically strengthens Jacinda Ardern's power over her own MPs while stopping Marama Davidson and James Shaw from publicly critiquing the Government's policies on climate change, biodiversity, family and sexual violence, and homelessness.
On election night, Ardern was both awarded and cursed by the biggest parliamentary caucus of any Prime Minister since Jim Bolger's giant 67-strong crew in 1990. When special votes are counted, Labour is expected to have a mammoth caucus of 65.
While overall the quality of Labour MPs in 2020 looks fairly good, the risk to any Prime Minister with such a large bunch of new MPs is that there will be at least a handful who prove destabilising.
In Bolger's case, the problem was his Government tacking much further to the right than the likes of Gilbert Myles, Hamish MacIntyre, Winston Peters, Michael Laws – and even Nick Smith, Roger Sowry, Tony Ryall and Bill English – believed they had signed up for.
Ardern's risk is that some of her 65 might decide they didn't sign up for the centrist and traditional – almost Holyoake-esque – Government she has planned.
The one potential threat to her personal power is if enough of those MPs decide to rebel either independently or in common cause with the Greens.
The co-operation deal with the Greens insures against this.
By including a commitment that the Greens will never vote against Labour on confidence and supply agreement, and will at worst abstain, Ardern has in practice extended her safe majority over the rest of Parliament from a 65-55 margin of ten to a massive 65-45 gap.
No conceivable rebellion in her own ranks could threaten her centrist policy agenda. The Prime Minister is absolutely right that the deal with further secure a strong and stable Labour Government.
But the Prime Minister has also effectively silenced the Greens on the issues most important to them, but on which Labour is politically vulnerable.
The deal allows the Greens to criticise the Government on issues where they do not hold a ministerial warrant but Ardern has confirmed that Shaw and Davidson will be subject to Cabinet collective responsibility on the policy areas the deal makes them responsibility for – climate change, biodiversity, family and sexual violence, and homelessness.
Cabinet collective responsibility is a stark and uncompromising doctrine. With some limited exceptions, it means that all ministers and undersecretaries must publicly support all Cabinet decisions "regardless of their personal views and whether or not they were at the meeting concerned".
And there's the rub. Shaw and Davidson will have no right to be at Cabinet meetings. Nor will either of them even be an Associate Minister of Finance to give them greater insight and oversight into the Government's overall policy programme.
Yes, they will be able to work with their bureaucrats to have Cabinet papers written about climate change, biodiversity, family and sexual violence, and homelessness. But then they will at best, be briefly allowed to perch at the end of the Cabinet table to present them, before the Labour ministers decide what the final policy will be. Whatever decision Labour makes, the Green ministers will be required to publicly support it.
It does the Greens no good that their backbenchers will still be allowed to criticise Government policy on climate change, biodiversity, family and sexual violence, and homelessness, because this would be to criticise their own leadership.
This arrangement couldn't be better for Ardern. Her Government has performed poorly in the areas for which Shaw and Davidson be responsible and now they will be silenced for nothing in return.
Under Ardern, there has been little progress, if any, in reducing New Zealand's greenhouse gas (GHG) emissions. Renewable electricity generation has gone backwards. Homelessness is as bad as ever and will get worse as quantitative easing further fuels house-price inflation.
Worse for the Greens, Ardern is making clear there will be no new GHG imposts on business or farmers other than those already announced, and has ruled out capital-gains, wealth or land taxes that might to something to slow the house-price bubble.
Especially given her soaring rhetoric about the "nuclear-free moment", the "housing crisis" and child poverty, the Prime Minister knows she is extremely vulnerable from her left on all these issues. Tonight's vote means the Greens will be blocked from criticising her on any of them.
Shaw and Davidson no doubt argued that it is better to have some control over climate change and homelessness bureaucrats than none at all.
But the realpolitik of the election result and tonight's deal means that, when push comes to shove, they will indeed be nothing more than inhouse greenwash for whatever Ardern decides is needed to keep her new ex-National Party supporters in the Labour paddock for 2023.
Matthew Hooton is an Auckland-based PR consultant, whose clients have included the National and Act parties. These views are his own.