At the end of the election campaign Tony Abbott observed that the big difference between an opposition leader and a prime minister was that the former was inevitably the leader of a tribe while the latter had to be the leader of a nation.

But Abbott so far hasn’t made the desirable transition he identified. His government is tightly wrapped in its tribalism.

One reason is that Abbott’s all-powerful private office, headed by chief of staff Peta Credlin, has a “them and us” mindset. And some ministers are still in opposition garb. Christopher Pyne and George Brandis are particularly fond of their war paint and spears.

The tribal style is one that sharply divides the world. Friends are to be held close, rewarded, defended right or wrong - it can be a bond stronger than reason, as one insider puts it. Many outside the tribe are viewed with suspicion or worse, seen as collaborators even if they aren’t formally part of the enemy.

Two current examples – the government’s treatment of the bureaucrats and the media - illustrate its approach.

This week the Canberra talk returned to Treasury secretary Martin Parkinson’s situation. Parkinson was given marching orders in September, with mid this year set for his departure.

It was an Abbott office decision based, in considerable part it seems, on Parkinson’s former role as head of the climate change department, where he assiduously promoted the Labor government’s policy (as you do, when you’re a career public servant). The Liberals also believed Treasury had been politicised under Labor.

Fairfax on Wednesday reported that before the election John Howard and Peter Costello had told Joe Hockey, set to be treasurer, that Parkinson should be retained.

Hockey – who’d had some “moments” with Parkinson in opposition – has been getting on well with him and the Treasury department generally. (The feeling appears mutual: according to one source, Parkinson has privately praised his boss but been less flattering about other ministers.)

Just imagine what Parkinson must be going through right now. He’s flat out helping Hockey put together a difficult budget; they’ve also just had the rigours of the G20 finance ministers meeting (in a touch of black irony, Parkinson’s wife is Abbott’s sherpa for the G20).

Through all this, Parkinson is living with a sacking (to be technical, he resigned) that is, on any objective measure, a highly unfair dismissal.

Ken Henry, former Treasury secretary under both Coalition and Labor, noted on Wednesday that “no government has ever thought it appropriate to remove the head of the Treasury and put in somebody who they think is … of a more comfortable political character”.

Henry said he did not know Abbott’s motivation “but if that is what is intended, then that would be a very disappointing move and quite a historic one”. Parkinson should be asked to stay on, he said.

Quizzed on Thursday about the sacking, Abbott described Parkinson as a very distinguished public servant doing a fine job, adding that “I look forward to continuing for some time to work with him”.

He then went on: “But you’ve got to understand that incoming governments do very much want to place their stamp on the economic policy of the country and that’s exactly what we are doing … That’s a very, very big change and we expect everyone in the system to be working enthusiastically with us as we reshape our country.”

This adds insult to injury, by implication casting an aspersion on Parkinson’s commitment or ability to implement the government’s objectives. That is a tribal rather than rational judgement.

It’s known that Parkinson would like to remain until after the November G20 meeting. Whether this happens is up to Abbott, and those who influence him.

The tribal network can extend from Canberra to Liberal states. It’s been suggested, rightly or wrongly, that this network was a factor in one of the secretaries who was sent packing in September failing to get a senior bureaucratic job in Victoria.

When there are appointments to be made to committees, statutory authorities and boards, the “us” and “them” filters are applied.

With staff jobs, tribalism is reinforced by the centralised vetting system, overseen by Credlin. While ministerial staffers are in a very different position from career bureaucrats, diversity can also be an advantage, but it’s not one much appreciated by this government.

The other stand-out case of the them-and-us syndrome is the government’s dealing with the media. News Corp is seen as part of the tribe. Government announcements, big and small, are routinely made through its papers. The ABC is regarded as sympathetic to the enemy tribe; it’s there as a perennial target.

Shock jocks such as Alan Jones and Ray Hadley are in the home tribe.They’re also chiefs in their own right, to be respected and on occasion feared, because they are not afraid to use their considerable power.

In a flaunting of tribalism, Abbott entertained a batch of conservative commentators at Kirribilli House hard on the heels of the election.

Tribalism is a driving force in the government’s determination to rewrite the Racial Discrimination Act, after a court judgment against News Corp columnist Andrew Bolt. If it had been Bruce Bolt from the Bay Bugle would the Liberals be turning the law upside down? Probably not. From the Coalition’s point of view, standing by Bolt won’t come pain-free: the ethnic communities and Jewish lobby can as tribal as they come and they’re agitated.

Within the broad Liberal tribe there are emerging sub-tribes (a better term in this context than factions). Joe Hockey has his close loyal followers. Malcolm Turnbull is a chief on his own, with colourful plumage, suspected by some colleagues of being too tolerant of “them”.

Turnbull recently alluded to the thinking when he said: “Some commentators on the conservative or the right-wing side of political debate have criticised me for launching Morry Schwartz’s new paper The Saturday Paper … They apparently would like me to be … the minister for right-wing communications or communications that agree with the Liberal Party.”

Tribalism will always be an important part of politics but an excessive dose can be a health hazard for a government. Talent can be lost on spurious grounds. Sections of the electorate can be alienated unnecessarily. Excessive time and energy can be spent hunting supposed enemies who don’t matter or aren’t even foes.

Too much tribalism makes for scratchy, ugly politics, and jars with voters who understand that the world’s not that black and white.

A government that knows when to pick its fights and for the rest is seen as reasonably tolerant and generous of spirit is a more attractive political package than one that always feels the need to reinforce the bunker.

Listen to the newest Politics with Michelle Grattan podcast with G20 sherpa Heather Smith here.