The almost indecent haste displayed by the party's panic-stricken but all-powerful factions in replacing Mr Rudd as Prime Minister provided ample illustration of just how cruel politics can be as Mr Rudd tried, but failed, to choke back tears following his ousting. His eviction from the top job was a brutal reminder of how swiftly public sentiment can turn against a supposedly-popular leader.
Once such a shift has occurred, it is nigh on impossible to reverse. Mr Rudd's caucus was well aware of that. By the time the putsch became "breaking news", Mr Rudd was a broken man.
On Wednesday evening, he was vowing to stand his ground and fight. By Thursday morning, he had accepted party unity must always prevail.
That brutal equation applies to all prime ministers - unless they walk first, because they have the prescience to realise they're about to get the old heave-ho.
Few do. And most definitely not when, like Mr Rudd, they have been in the job for little more than two years.
What will be exercising minds in the National Party on this side of the Tasman is the amazing speed with which Mr Rudd went - to borrow a phrase - from hero to zero.
Ironically, his rapid demise should give New Zealand Labour considerable heart. Mr Key's poll ratings as preferred Prime Minister might still be at stratospheric levels - and, as a consequence, National's are not far behind. But so were Mr Rudd's until the start of this year.
That Mr Rudd's ratings, along with those of his party, have since gone down the gurgler might suggest Mr Key - so far impervious to Labour's largely ham-fisted attempts to discredit him - is not necessarily invincible.
Unfortunately for Labour, there is a lot more that separates Mr Rudd and Mr Key than there are similarities.
Certainly, there are question marks as to what either really stands for. However, whereas Mr Rudd promised policies based on high-minded principle, Mr Key based National's policy development on what is going to work, as well as straight-out party ideology.
For example, Mr Rudd described fixing climate change as "the greatest moral challenge" facing mankind.
He then promptly postponed the introduction of an emissions trading scheme as being in the too-hard basket, a decision confirming perceptions he was only interested in staying in power.
While similarly claiming the moral high ground on Japanese whaling, he also prevaricated on a promise to take that nation to the International Court of Justice.
In contrast, Mr Key promised, and delivered, a watered-down version of Labour's emissions trading scheme. Had it got rid of the scheme altogether, National could have won substantial brownie points from the business and farmer lobbies.
The need for consistency will influence the Government's final decisions on mining on the Conservation estate. While National will likely back away from the more contentious elements in Gerry Brownlee's mineral resources stocktake, it will not make a complete retreat.
Mining is one issue where National made the mistake of leaving a political vacuum for opponents to fill - something Mr Key learned from Helen Clark not to do.
Mr Rudd let dangerous vacuums develop on major issues, particularly on the question of the refugee boat-people.
One marked similarity between Mr Key and Mr Rudd is that both quickly rose up their respective parties' ranks while in Opposition. Both benefited from leadership vacuums which they ultimately filled.
Mr Rudd's problem is that he failed to build a power base on his way up. That proved extremely costly in recent weeks. Lacking a power base in a highly-factionalised party meant he lacked allies to defend him.
In terms of leadership style, the pair are polar opposites. While demanding of his ministers in terms of expecting results, Mr Key is more laid back and flexible, giving his ministers room to breathe and get on with the job as they see fit. At times, oversight from above has been too lax.
Mr Rudd, on the other hand, has been constantly accused of being autocratic. Many decisions were not made by the full Cabinet, where issues could be fully explored for hidden fish hooks. The Prime Minister's office also played a dominating role, which alongside a failure to consult, bred resentment. That did not matter when things were going well and the ALP was doing well in the polls, as was the case until Tony Abbott took over leadership of the Liberal Party in December last year.
Mr Abbott has managed to turn the polls around to the point that some have registered significant margins over the ALP in recent months, ultimately leading to Mr Rudd's downfall. Mr Abbott's elevation is testimony to the degree to which a new leader can shake up the political dynamic.
Phil Goff's struggle to gain traction would normally bring the kind of fate suffered by Mr Rudd this week. However, Shane Jones' disgrace and David Cunliffe's unpopularity in the Labour caucus has marginalised two MPs who were always outside chances anyway. And it is too soon to consider anyone from the 2008 intake.
Mr Goff may not be able to breathe easy, but Mr Key can.
- John Armstrong is political correspondent for The New Zealand Herald
