The unanimous judgment of the Supreme Court is significant and unusual.
The judgment has been delivered in record time and all five justices concurred in the reasoning and primary decision: namely that "the partial privatisation of Mighty River Power will not impair to a material extent the Crown's ability to remedy any Treaty breach in respect of Maori interests" in the Waikato river. "For that reason" the court dismissed the appeal.
It is important to note that the decision does not set out to determine the nature and extent of Maori rights to water. Rather, it concludes that there are enough protections now for those rights, given Crown assurances. Neither did the Maori Council seek to argue the case in terms of the effect of the Crown's share sale on aboriginal title claims to the assets of the power- generating SOEs.
The court therefore proceeded "on the basis that the proposed privatisation will not have any effect on such claims". Even so, it has made significant findings.
First, the court overturned the High Court on whether the Crown's share sale decision was susceptible to judicial review.
Second, the court held that the Crown's consultation which followed the urgent Freshwater Report was not shown to be inadequate.
On the ultimate question - whether the share sale decision was inconsistent with Treaty principles - the court relied on Privy Council authority in holding that Treaty compliance requires the court to make its own assessment.
Given a host of factors concerning Crown policy and engagement with Maori in relation to freshwater, and assurances given by the Deputy Prime Minister and the Attorney-General in affidavit evidence, the court made its ultimate finding that the share sale decision would "not impair to a material extent" the ability of the Crown to recognise Maori interests in freshwater and geothermal resources.
In other words, the Crown has done enough. At the same time, it has made promises and a strong unanimous judgment suggests the court is minded to hold the Crown to account in future. In the case of the Deputy Prime Minister these assurances include expressions of confidence that the mixed ownership companies programme will not compromise the Government's "work to achieve recognition of and redress for Maori rights and interests in water and geothermal resources".
The court did flag the importance of the current power-generating infrastructure to the wider New Zealand economy as a high-level policy factor the court could not ignore in assessing what protective measures for Maori rights was appropriate.
So a win for the Crown, but the qualifications of the court need to be heeded. The court may have closed the Maori Council door, but they have opened a window.
Mai Chen is a partner at Chen Palmer and adjunct professor at the University of Auckland Business School.By Mai Chen Email Mai