Astute political scientist that she is, Helen Clark read the mood of the electorate accurately on Saturday night when she surprised everyone by standing down as Labour leader.
She must have been well aware she was on borrowed time. Opinion polls had voters declaring it time for a change more than two years ago. This desire even predated John Key's seizing of the National Party leadership in November 2006.
Saturday was the voters' first chance to do something about it. Little subplots like party president Mike Williams' trip to Melbourne to dig for dirt were great ammunition for the bloggers, but they were neither here nor there in this greater picture. The tide had gone out for Labour long before that.
Even if Mr Williams had returned triumphant, smoking gun aloft, I have my doubts many voters would have cared.
Indeed, but for the extremism of National's former leader, Don Brash, National might well be celebrating a second-term victory this week. It's easy to forget that back in 2005, Labour only narrowly pipped National to become the single largest party.
It was the Herald-DigiPoll survey of August 2006 which first signalled the fickleness of the voters. It had Labour on 38.7 per cent to National's 46.4 per cent. The following month, with Dr Brash taking time to sort out his marriage problems, the One News Colmar Brunton poll showed an even wider gap in favour of National.
At the end of November, Mr Key replaced Dr Brash as leader and Labour briefly recovered its popularity. Sadly for them, it was to be the dead cat bounce of stock-market lore.
After the summer holidays, Labour slumped again and National soared skywards. In recent weeks, this two-year-long gap began to close slightly, but the desire for change inexorably won out.
This wasn't an election won over matters of policy. National made certain to avoid that trap. Old controversialists such as Maurice Williamson were slapped down for being specific on matters like tolling Auckland motorways. Mr Key and his tacticians were determined this time not to frighten the horses the way the radical Dr Brash had. Instead, they carefully matched every Labour move with a bland, less-than-specific counter-promise of their own.
At National's election-night party they even had a band of Indian drummers pounding away in the background. How Labour Party can you go? And like supermarket shopping, when the products on display look similar, how many of us get around to reading the small print?
As she hands over to Mr Key, Helen Clark can hardly be critical of someone who sat at her feet and borrowed so freely from her centrist operator's handbook. It will now be interesting to see whether he goes a step further than she did, and brings the Maori Party into his web.
Whether the political new boy can master the MMP environment is the big question. When Helen Clark became Prime Minister in 1999, I spoke to former colleagues and acquaintances about her prospects. Her mentor and former university colleague Professor Bob Chapman pointed to some of the pitfalls of governing under a proportional system.
"MMP politics is the hardest kind to work in. It involves a great deal of self-abnegation. It demands putting up with compromises you would really rather not have to.
"For idealistic people, this containing themselves when they can only obtain half the loaf, or a quarter, is very hard."
He said: "Helen understands the limitations of the situation and she'll try her level best."
A cynic would note that, unlike Helen Clark, Mr Key has shown no signs of having much in the way of idealism to wrestle with; therefore the job will be easier in his case.
But as David Lange said to me at the time, there's more to MMP than that.
He singled out his former colleague's "capacity to manage and direct by a clear, calculated rationality, which is very hard for emotional political types to understand". He noted admiringly that she knows where the levers of power are in a way not many MPs do.
He thought New Zealand had reached the season in politics where Helen Clark's steady, "rather ruthless" analytical style of leadership was needed.
Whether her successor can match these skills, we'll have to wait and see.