If you opened a bank in which to put all the political capital invested over the years into not conceding a point to the other side and then lent it out at an exorbitant interest rates to political parties who suddenly realised they had sprayed quite a lot of the stuff against the wall, you would have a nice little earner on your hands.

It's one of those mysteries of politics that politicians so often dig in on some point — tactical, or policy — not because it is a point of high principle, but simply because they are not going to give the slightest bit of ground, nor make the slightest concession, to the other side.

It's been a habit on splendid display, along with the not-so-splendid results, in Canberra this week.

It encompasses everything from the continuing exercise in machismo that is the Angus Taylor/Clover Moore saga (which it is turning more into an exercise in masochism — but more of that later) to the Government's shock at its defeat in the Senate on industrial relations legislation.

Often new governments — and for that matter, new oppositions — start their terms in government promising to be sensible about how they conduct themselves: offering bipartisanship and civility where possible.

Most recently, consider the flak Labor leader Anthony Albanese got in his first few months in the job for agreeing to some pieces of government legislation.

But almost inevitably the civility doesn't last. Someone does something uncivil, and it is on for young and old.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 43 seconds 43 s Scott Morrison defended the call to NSW Police Commissioner Mick Fuller during Question Time.

The Coalition's embrace of machismo

But there is more elevated level of this whole game which both sides have played over the years and — it must be said — they have played to their own cost.

Here are a couple of examples. Paul Keating, as prime minister, decided to back his Health Minister Carmen Lawrence when she was under assault from the Liberal Party, which had even called a royal commission into her actions as WA premier.

He refused repeated calls for Lawrence to stand aside from her portfolio while the royal commission was under way.

Mr Taylor sent a letter to Clover Moore apologising "unreservedly" for relying on figures in media commentary without clarifying them. ( ABC News: Kevin Nguyen/Toby Hunt )

On one level, you could say it was very noble of the Prime Minister to back someone under such political attack.

But there have always been tests other than actual wrongdoing associated with judgements about when ministers should stand aside.

These have been: is the ministers' continuing presence a distraction, or even a detriment to the government going about its work; and/or is the controversy in which said minister is involved a distraction from their work for us, Mr and Mrs Taxpayer?

These tests should still be the ones that are applied by prime ministers in making judgements about such things.

But in the past decade or so, the Coalition in particular has become very determined to not make concessions when its ministers are in difficulties.

And, too often, that has been based on the idea of not giving a "scalp" to the opposition, rather than on what is in the government's best interests — and for that matter the best interests of the minister involved, and the prime minister.

John Howard began his long time in the prime ministership upholding standards that seemed almost too high and at one point was losing ministers at an unseemly rate for what would these days seem relatively minor offences.

Having been so wounded, Howard erred in the opposite direction in his later years in office.

Coalition's tone plays into Labor's hands

The Coalition's embrace of machismo has gone even further though in recent years, particularly under Tony Abbott and Scott Morrison.

It doesn't just affect decisions over wounded ministers, but debating points too.

You sense it in the Coalition's still tortuous language about climate change and natural disasters.

Brian Hartzer had been in charge of Westpac for nearly five years. ( ABC News: John Gunn )

And it seemed present this week in the conspicuous difference in the language being used about Westpac's extraordinary 23 million breaches of money-laundering laws, compared with the more hysterical tones of its language about the dangers posed by unions which needed to be reined in by its "Ensuring Integrity" Legislation.

In the wake of the Westpac revelations, the prime minister told ABC radio early in the week that the future of Westpac chief executive Brian Hartzer was "[a] thing that the board and the management need to determine themselves".

"It's not for the government to say who should be in those jobs or not, but they should be taking this very seriously, reflecting on it very deeply, and taking the appropriate decisions for the protection of people's interests in Australia," Scott Morrison said.

"These are some very disturbing, very disturbing transactions involving despicable behaviour."

Labor, understandably, saw an opportunity, and Tony Burke asked Morrison in Parliament how could "23 million breaches of the law be a matter for the board if you're a bank, but legislation before the Parliament right now says that three breaches of paperwork can get you deregistered if you're a union".

It was Attorney-General Christian Porter who answered the question, saying: "when the opposition talk about paperwork, look at what this bill is actually being targeted towards — assaulting police, five times; assault by kicking, five times; wilful trespass, seven times; resisting arrest, five times; theft; attempted theft by deception; and intent to coerce, nine times.

"It's paperwork! And that was just one bloke. That was just one guy. That was just John Setka."

Spending political capital, and for what?

Apart from Setka's expulsion from the ALP blunting the potency of this attack, the very different tone of the language played into Labor's hands, and into the reasoning of the crossbench and particularly One Nation when it was finally time to consider whether it would back the industrial relations laws.

But more than anything else, the dogged determination to protect Taylor — at least until the Parliament rises — when the Minister has offered no rational explanation of how he came to be releasing doctored documents, defies not just common sense but self-interest.

Plenty of Coalition heads were shaking at the Prime Minister's approach on this issue, even before the storm broke about his call to the NSW Police Commissioner during the week.

Having dug himself into a difficult corner, Morrison went even further on to the attack, trying to rope in claims about police investigations into both Julia Gillard and Bill Shorten, but coming spectacularly undone on that by getting his quotes wrong.

Think about the two underlying messages of the government and opposition as the political year ends.

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The government's is "we are better than Labor". We have a "stable and certain economic plan".

Labor's message is much more basic: "Scott Morrison is not the ridgy-didge bloke from the Shire that you think he is".

This week, the Coalition tried to defend itself by saying its behaviour was no different to Labor's: Labor figures had not stood down during police investigations, so why should Taylor?

And this week, Labor finished the week with Morrison being caught out misleading the Parliament, and appearing for all the world like he didn't, he was doing what he could to avoid being seen on camera admitting it.

And defending the indefensible behaviour of his minister.

So much political capital expended. So little return.

Laura Tingle is 7.30's chief political correspondent.