Cullen on the constitution

Sir Michael Cullen writes in the NZ Herald:

It is no great secret that I am, by and large, a constitutional conservative, supportive of parliamentary supremacy, and therefore opposed to a written constitution which has the status of supreme law, not fussed about New Zealand continuing to be a constitutional monarchy, a little sceptical about how much of the burden of defining a nation the Treaty can bear, and generally holding the view that the onus of proof in relation to any proposed constitutional change lies with the proponents of that change.

I agree the onus of proof for constitutional change should lie with the proponents.