Malcolm Turnbull still faces many tests, including questions about his promotion of under-fire minister Mal Brough. But so far, the Prime Minister has vindicated the idea that leadership coups can actually help improve our politics, writes Barrie Cassidy.

It's time to write in support of leadership coups - and not just those practised by opposition parties, but the real deal: those that dump prime ministers mid-term.

The general consensus seems to be that it's the revolving door of leadership that has caused the electorate to become disillusioned with politics.

But I would argue it's not the sackings of leaders, but rather the root causes of those sackings, that up until now has been the problem. The coups happened because of a breakdown in governance and deep disappointment with the quality of leadership in the first place.

Certainly, it is becoming increasingly clear that the latest coup - Malcolm Turnbull knocking off Tony Abbott - is more a solution to political malaise than an ongoing episode in a broken system.

Sorry, this video has expired Barrie Cassidy reviews the week in politics on News Breakfast

Look at how the public has reacted to Abbott's demise, as evidenced by the major opinion polls.

Pollster Andrew Catsaras has crunched the numbers and found that since the change of leadership, 1,100,000 voters have switched from Labor to the Coalition.

In two-party-preferred terms the Coalition has achieved a 7.4 per cent swing towards it to now stand at 53.7 per cent. As Catsaras points out, in a neat twist, the Coalition now stands exactly where Labor was before Abbott's sacking.

There is a long way to go before history can ultimately judge the Coalition's move against Abbott. Turnbull is yet to be tested by a budget. He may have exercised poor judgment by bringing the Special Minister of State, Mal Brough, back into the ministry when the jury was still out over his involvement in the James Ashby affair. And there could be serious questions down the track on Turnbull's handling of the NBN.

But nevertheless the evidence suggests the electorate is mightily relieved to this point that it is him - and not Abbott - who now calls the shots.

Harder to justify was the sacking in 2010 of Kevin Rudd for Julia Gillard. Certainly that shocked the electorate in a way that the Abbott defeat did not.

Having said that, it can be explained.

Rudd was not cut down because of poor opinion polls. He was sacked because he ran a dysfunctional government; he gave power to staff ahead of elected MPs; and he treated too many people with disdain and contempt.

As one senator told me at the time, had he simply ignored his backbench he might have survived. But he chose to abuse them as well.

None of this is exaggerated. Never before, with just the whiff of a challenge, have the numbers tumbled so quickly.

It was a testament to his style - and a measure of the resentment towards him - that Gillard backers confidently predicted on the night that if Rudd allowed it to go to a party room vote, Gillard would have captured perhaps 80 of the 112 eligible votes.

Some will always argue that the people decide the prime ministership and only they can take it away. But they don't choose the leader, and under the Australian system, they never will. The electorate votes for local candidates. That decision is heavily influenced by who leads the major parties, but that's all. It is the purview of the party room to decide the leadership.

Rudd was replaced because the system had broken down. He tried to govern in a way that threatened time-honoured processes.

Whether or not he could have gone on and won an election is almost beside the point. But I would argue his situation was rapidly deteriorating and was likely to get worse.

Rudd was going to win easily when his opponent was - ironically - Malcolm Turnbull. At the time Turnbull's personal approval rating was similar to that Shorten is now experiencing.

When Abbott took over, he immediately exploited Rudd's agony over climate change in a way that Turnbull could not. Suddenly, Abbott had Rudd covered.

It is often said that Gillard didn't really win anyway, being forced to stitch together a fragile minority government. But Gillard, without question, would have achieved majority government had her internal opponents not leaked against her during the election campaign. With the benefit of a majority, her fate could have been very different.

It is hard to imagine a lower act in politics than to leak against your own leader in a campaign. It is one thing to leak mid-term in an effort to destabilise the leader and mount a challenge. It is another thing altogether to leak with the sole purpose of causing your own party to lose an election. Yet that's what happened in 2010.

Now, history is repeating itself.

We are seeing internal opponents of Turnbull using national security and the aftermath of terrorist attacks to try to portray him as weak and indecisive. Not as bad as 2010, but very poor form just the same.

The other recent sacking of a prime minister that allowed Rudd to return to fight the 2013 election can be spun in all directions.

Gillard had fought so hard against the odds. But on the evidence she was headed for a disastrous defeat.

The most pragmatic in Labor ranks wanted to do two things: save some furniture, which they did, and put to rest any notion that had Rudd resumed the leadership he would have won the election. He got his chance, he didn't win, and he was gone for good.

The leadership merry-go-round started because the process had been corrupted. Abbott - in opposition - thrived on that. In government, he didn't measure up. The system took care of that.

Barrie Cassidy is the presenter of the ABC program Insiders. He writes a weekly column for The Drum.