Paul Moon writes on the the role of the monarchy in New Zealand after Prince William's visit.

The issue of New Zealand becoming a republic is one of those exposed nerves of national identity that twitches every time it is touched.

To mention the prospect is a cue for those both for and against republicanism to get agitated, thump their chests as they reaffirm their positions and then, after a few days when the heat of the argument has cooled, it's back to life as usual.

This predictable reflex response to the continuing role of the monarchy in New Zealand masks the fact that both sides - monarchists and republicans - to some extent have missed the constitutional point.

The reality is that New Zealand already is a de facto republic, and has been for more than six decades. Yes, the Queen is still the de jure head of state, but very much in a token role - a bit of colonial garnish that so far has not been picked off for fear that perhaps some offence might be caused in the process or because it is a comforting tradition.

I can imagine some readers already rushing to challenge me - prepared to cite chapter and verse "proving" our continued status as a monarchy. I have some sympathy for their position, but would urge them to consider the fact that our governments operate entirely without royal interference, and that the deference shown to the Queen is primarily procedural, cultural and almost ritualistic rather than material - something all our governments since the end of World War II have readily appreciated and demonstrated.

Under closer examination, the argument over whether New Zealand should become a republic therefore looks very much like a cruel joke played on credulous children. The answer is already known, but still, the infants jump up and down and screech for their preferred choice.

Moreover, the important arguments against the monarchy - particularly a hereditary one like Britain's - have already been won in a very convincing manner. John Milton, one of the most forceful and certainly the most eloquent republican in English history, easily demolished what he interpreted as the blasphemous notion of the divine right of the monarch (something that subsequent kings and queens grudgingly came to accept), while Edward Gibbon rightly pointed out that a hereditary monarchy was a form of government that presented "the fairest scope for ridicule".

There cannot now be a serious debate about maintaining a fully functioning monarchy because the British monarchy itself has long since also retreated from the role. Indeed, the expansion of the pomp and ceremony surrounding the royals sometimes seems to have grown in inverse proportion to their real purpose in government.

To claim to be a fervid republican or a committed monarchist in the New Zealand context is therefore almost meaningless. Replacing one titular head with another one would do nothing in practice to alter the way in which the country is governed. In fact, we have now come close to achieving one of Milton's most precious ambitions for England: that the people, and not a monarch, are the true sovereigns of the nation.

This is where the real challenge lies, and the call of brave politicians ought to be heard. Shuffling one ornamental head of government away to be replaced by another is no real change at all. Perhaps we should trust ourselves enough to take that final step and have Parliament as our sole sovereign authority.

* Dr Paul Moon is professor of history at AUT University.