Nearly three decades after the introduction of MMP and multiparty governments there should be a greater level of understanding about their finer points than often appears to be the case.

The reaction to the despicable outburst from the Deputy Prime Minister at the weekend highlights this. To be very clear, there is no justification for the remarks Peters made comparing the previous government – in which he was Deputy Prime Minister for three years – and its co-governance policies to Nazi Germany. His comments were no more than a very cheap attempt to gain a headline, and one more in a long line of racial slurs that he has used over the years to maintain his appeal to the egregious bigots who are his constituency.

But calls for the Prime Minister to discipline him over his remarks misunderstand the power of the Prime Minister in a coalition government. According to the Cabinet Manual, the Prime Minister is the head of government and responsible for the overall conduct of its policy. Ministers are responsible to the Prime Minister for the implementation of government policy as agreed by the Cabinet. The specific party responsibilities of both the Prime Minister and other Ministers are separate from their governmental responsibilities. As Speaker Margaret Wilson ruled in 2008, “The Prime Minister is not responsible for the decisions of another party.”

The Prime Minister’s official powers in a situation like last weekend’s speech are therefore quite limited, especially so since the Deputy Prime Minister made it clear that he was speaking as the leader of New Zealand First. Therefore, no matter what he thought of the comments, the Prime Minister had virtually no room to act, unless he felt that the comments risked the stability of the whole government, which they did not.

While that may be the official perspective, the political reality is somewhat different. Although the Prime Minister clearly disapproved of what was said, his limited ability to act left a public perception of weakness on his part, and a feeling that once more his errant deputy had been able to get away with it.

This is, of course, precisely what Peters was seeking. Ever since the coalition was formed, he has been jostling to assert the superiority of his flawed experience over the politically inexperienced Prime Minister, and the ACT Party leader. Peters wants to be seen as the dominant power within the government, even if his party is the smallest part of it. The weekend’s remarks were thus a continuation of the pattern established at the media conference announcing the formation of the coalition last November when Peters used the occasion to launch his extraordinary claim that the media had been bribed.

So far, both the Prime Minister and the ACT leader have lacked the political skills to counter this behaviour. Consequently, they have ended up treading around their fair-weather partner on eggshells, too wary of giving him any opportunity to walk away from a coalition, as has happened previously. This simply reinforces his contention that he and by (distant) association New Zealand First, hold the real power within the government.

Under the coalition agreement, New Zealand First is supposed to cede the Deputy Prime Minister’s role to the ACT Party in just over a year’s time. In the meantime, a near certainty is that there will be more outbursts of the type seen at the weekend as New Zealand First seeks to retain its political relevance. All of which will make the Prime Minister’s already difficult political management that much more challenging.

Another near certainty is that as each new situation unfolds, the populist media will demand the Prime Minister act, and lambast him when he cannot, rather than calling out New Zealand First’s behaviour for what it is.

It all stems from a failure to move beyond the bipartisan world of the old First-Past-the-Post system. While there is still a government and an Opposition as there was previously, governments and Oppositions today are multiparty in nature. They work together on the issues they agree upon and retain their own positions (and identities) on those where they differ. But the confrontational nature of our Westminster political system means too many observers still see the political contest in the black and white terms of the past.

Yet the concept of one government composed of many parties is not a difficult one to grasp, although it does require more subtle understanding than the commentariat often demonstrate. The same applies on the other side of the fence as well, where there seems to be a constant struggle to work out where Te Pati Māori – which by its own admission operates on a different social and cultural paradigm – fits.

None of this is a justification of the Deputy Prime Minister’s comments last weekend, more an attempt to explain the wider circumstances behind them. It is a task that might reasonably have been expected of the media present at the time, but they were too readily seduced by the immediate, salacious drama of the remarks themselves to want to look too closely at some of the underlying realities.

That was exactly what Peters wanted, and, like puppets on a string, they duly obliged him.