No one ever believed it was a cabinet in more than name. The cabinet is the key decision-making body in individual governments of the Westminster variety. The type of government it represents is known as cabinet government. Its members are drawn from just one side of politics.

The cabinet system operates according to key rules, including solidarity, secrecy and collective responsibility, none of which apply to the national cabinet, though for a time that fact was glossed over. The image of the nine political leaders coming together to respond collectively to the national health and economic challenges prevailed. It was given added gloss by the technical innovation of virtual meetings and by the regular reports to the nation by the Prime Minister which followed each meeting.

In reality it was a make-believe body, given a fancy name in order to give it status and authority in the eyes of the public. As such it potentially was an important innovation, which would come to be identified with the Prime Minister who presided over it. Scott Morrison trumpeted it as an important institutional development. He also talked down COAG as a body which had failed to build the unity and decision-making capacity which Australia needed.

The new national cabinet was also seen as more than just an institutional development but a new way of doing politics. This was going to be one of the ways in which life after the pandemic was going to be different. Politics in the future was going to be more reasonable and less partisan. Ideology was dead, and was to be replaced by science and evidence.

Just as the political leaders made a big deal about how they were taking advice from the health experts, some optimistic commentators saw this as a new approach to all contentious political issues, including climate change. Hopes were high that the new political world would be different. After all, the Coalition government was instituting interventionist economic policies that it once would have sneered at.

We now know that the new way of politics, led by a new institution, is not going to happen. It has all unravelled. The Prime Minister now has a new image for the national cabinet. It is like a bus which political leaders can board or not board as they wish. So much for cabinet solidarity. The bus leaves the bus stop whether everyone is on board or not.

The new road map towards an open-borders Australia with a target date of Christmas was announced despite the absence of full commitment by the state premiers. Western Australian Premier Mark McGowan refused to sign on, and other premiers, including Queensland's Annastacia Palaszczuk, maintained reservations.

If this was a true cabinet, the majority would have prevailed and the minority would have accepted the decision. That did not happen.

What got in the way were legitimate political differences and party politics, which are sometimes difficult things to untangle. It began with arguments about school closures and grew into differences about border closures. Slowly, fragmentation within the federation grew.

Even while the political leaders themselves maintained civilised discourse and public unity, others broke ranks. Coalition backbenchers and federal ministers began to criticise Labor state and territory leaders over their handling of the pandemic and the economic recovery. Federal Labor defended its state counterparts.

We should not have been surprised. Party politics is deeply embedded in our Australian psyche. It is not just an electoral competition for government power played by the party machines - it runs right through our social values.

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Two factors have driven the eruption in party politics.

Firstly, while the national cabinet contained an even mix of Liberal and Labor leaders (five Labor and four Liberal-National) the serendipity of the 2020 electoral cycle has focused on Labor. The byelection for the federal Labor seat of Eden-Monaro was followed by the Northern Territory election where Labor retained government, and in October there will be elections in the ACT and Queensland, where Labor is in government. Electoral politics inevitably generates heated party politics.

Secondly, the difference in performance between the states inevitably invited party-political comment. Initially there were the differences in health and economic responses, especially in relation to border closures. Palaszczuk angered Morrison with her hard border closure of Queensland, the tourist state. Yet Liberal states like Tasmania and South Australia were equally tough on borders without drawing the same criticism.

Then came the second wave of the pandemic in Victoria, and the hard lockdown of that state by Daniel Andrews, the Victorian Premier. Now the political gloves are off. Relations have broken down completely between Andrews and the federal government, including the Victorian-based Treasurer, Josh Frydenberg, whose criticisms have been extremely harsh.

The Liberal Prime Minister, himself based in Sydney and not Canberra, has drawn invidious comparisons between NSW and Victoria, singling out the Liberal NSW government of Gladys Berejiklian as the "gold-standard'' for keeping economic activity flowing while dealing with pandemic hotspots. Other states and territories with successful records have been forgotten.

The twin casualties from all these developments have been the idea of a successful new institution, a national cabinet, and the hope of a new ideology-free national politics. Both were always make-believe.