Sir Geoffrey Palmer, the politician responsible for putting Treaty of Waitangi clauses into modern legislation, is delighted with the Supreme Court water case decision.
It's not that he is thrilled that the Crown got the go-ahead to partially privatise Mighty River Power.
It's that the Supreme Court asserted its right to judicially review a sale of the shares and that it reached a unanimous decision.
Part of the Crown case was that the pending sale of shares in the State-owned company would be undertaken under its common law rights to sell its property, not under statutory power, and therefore the court could not review the sale.
High Court judge Ron Young accepted that position. He decided the sale was not reviewable. Even if he was wrong, there was no breach of the Treaty protections in law. The Supreme Court disagreed with Justice Young, and said the sale was reviewable.
But it did not find the Crown had breached its obligations.
That allowed the Maori Council appellants to legitimately claim it had gained something in the case despite not stopping the sale.
Sir Geoffrey thinks the decision was "undoubtedly correct".
"I was also very pleased, as a matter of judicial statecraft, that they had a unanimous decision. It's really important on big issues like this where the Supreme Court is telling us what the law is, and there is no appeal from that. It is very important the Supreme Court speaks with one voice."
The famous Lands case of the Court of Appeal in 1987, which established the principle of partnership underlying the Treaty, was unanimous but was delivered in five separate judgments.
"I take the view, as a lawyer, that (for) the higher appellate courts, whose job it is to clarify the law and to settle it, it is better for them to speak with one voice whenever they can. It leads to certainty and it leads to clarity," Sir Geoffrey says.
The Treaty protection clause is clause 9 in the State-owned Enterprises Act 1986: "nothing in this act shall permit the Crown to act in a manner that is inconsistent with the principles of the Treaty of Waitangi".
The same clause was imported as clause 45 Q into the Public Finance (Mixed Ownership Model) Amendment Act 2012 - after quite a hoo-ha because Treasury had recommended that there be no Treaty clause in the new act.
Sir Geoffrey doesn't mince his words about Treasury's advice.
"Treasury has not covered itself in glory in the advice it gave to the Government on this matter because I don't think the Treasury understood the nature of the legal issues.
"The Treaty issues go back a long way and the idea that you could brush aside section 9 of the State-owned Enterprises Act by just saying 'here's a new statute and it hasn't got Section 9 in it' was naive in the extreme. You don't want to get your advice on constitutional and legal matters from the Treasury."
Sir Geoffrey, as Attorney-General in 1986, is variously credited and blamed for getting the unspecific Treaty clause inserted into the State-owned Enterprises Act.
The Court of Appeal interpreted its meaning in 1987 and since then - whether by design or negligence - Parliament has largely followed a similar pattern: putting Treaty clauses in laws and allowing the courts to interpret them.
When former Deputy Prime Minister Sir Michael Cullen had just been made Attorney-General in 2005 and was warning the courts against judicial activism, he made an exception over the Court of Appeal Lands case, saying it had not been a sign of "improper judicial activism" because the fact was Parliament had left the courts to perform that role of interpretation and they could not be fairly criticised for doing so.
This week's Supreme Court decision was delivered coincidentally against a backdrop of a review of New Zealand's constitutional arrangements, including the place of the Treaty of Waitangi. The day before the decision, the review panel, which includes Sir Michael, launched a website and national "conversation" ahead of its recommendations to Government by the end of the year.
Inevitably, issues of a written constitution and whether it should be supreme law (allowing laws that are inconsistent with it to be struck down by the courts) are about the relative power of Parliament and the courts.
Sir Geoffrey does not believe that this week's decision by the Supreme Court would have been much different if the Treaty were part of a written constitution.
"It wouldn't be all that different because all you would be doing is interpreting what is very general language (in the Treaty) in specific later situations and I don't think that would make very much difference in a case like this. The constitutional arrangements in New Zealand are infinitely flexible and always evolving and the result of that is that there is no place to stand for our constitution," Sir Geoffrey says.
He refers to the work of his son, Dr Matthew Palmer, who argues that the Treaty should be given statutory legal force and subject to an independent new Treaty of Waitangi Court.
One of the claims of the Maori Council case was that the exercise of all New Zealand laws, whether or not they have a Treaty clause in them, should be consistent with the Treaty of Waitangi. The judgment was silent on that claim, upholding the status quo that the treaty has the force of law only when it is specifically mentioned in statutes.
Sir Geoffrey says the current situation is "very untidy altogether. The Treaty is half in and half out of the law. It's only in it to the extent that Parliament says it's in it and it doesn't say that in many fields at all."
Having the Treaty as part of a written constitution would make the situation less fluid. "Every time you got a case out of the Supreme Court you'd know more about it and you'd be building a wall of some coherence and clarity, brick by brick, decision by decision."