This week marks a significant event in New Zealand’s unwritten constitution. It concerns the “rule of law” – an important constitutional concept – and how we recognise that concept. It also concerns the way the system operates, and the value of having an interested and engaged Opposition in Parliament.

First off, let’s look at what the rule of law is. I’ve said that it’s important, but it’s not an easy concept to describe. At quite a simple level, it is the idea that the vast power of the state should be controlled by law. Parliament makes laws, and courts enforce laws, so that there are expectations and restrictions on how public power is exercised. That’s important from a philosophical point of view, because constitutions like to control public power, but it’s also an important protection for individual citizens who want to live in a free society.

Because it’s an amorphous concept, it’s not always clear how the rule of law gets recognised in New Zealand. One important way it is recognised is in s 3(2) of the Supreme Court Act, which provides “Nothing in this Act affects New Zealand's continuing commitment to the rule of law and the sovereignty of Parliament”. That’s a symbolic reference, and not something that the courts have applied directly, but that symbolism is still important. It’s included in the legislation that establishes the highest court in New Zealand precisely for the reason that we want to show how important the rule of law is as a fundamental value.

Is s 3(2) of the Supreme Court Act all there is to the rule of law in New Zealand. No, clearly not. But it’s important nonetheless because it shows Parliament takes its rule of law obligations seriously in the most obvious way it can – through legislation.

So far, so good, except that last year the Government decided that the legislation governing the courts needed to be updated. And part of that update would remove s 3(2).

The Government defended that decision by arguing that s 3(2) didn’t do much anyway, and the rule of law was such an obvious and pervasive constitutional protection in New Zealand that a statutory reference to it wasn’t needed. That thinking wasn’t very convincing, as I have noted elsewhere (see “Legislative Reference to the Rule of Law” [2015] New Zealand Law Journal 251‑252 which I co-wrote with Alexandra Blair). But the Government was unmoved, and the proposal to remove s 3(2) remained on foot.

Until yesterday, that is. For whatever reason, Labour Opposition MP Jacinda Ardern chose to take issue with the Government’s proposal. She worked behind the scenes to drum up support for a Supplementary Order Paper that would reinstate s 3(2). It took some time, but it worked. Statutory recognition that the rule of law is a constitutional value in New Zealand will remain.

I think that’s important for 2 reasons. First, because the rule of law is important, as I’ve already mentioned. But second, and perhaps most interestingly, this episode has given us something of an insight into how Parliament deals with constitutional issues. Section 3(2) will be retained because one MP decided that its constitutional significance was important, and she managed to convince enough other Parliamentarians that they should take it seriously as well.

New Zealand’s constitution is sometimes maligned for being flexible and uncertain, but Jacinda’s efforts show that it still works well (eventually) when enough people in power take constitutional values seriously. At for the moment, at least, they do.