Opinion - National will be praying this month's political tumult stops with the centre-left, but Labour will be hoping for something larger still, writes Jon Johansson.
Tom Scott published a great cartoon in early 1988 after the ground shifted on the Fourth Labour Government and its popularity hit the skids once its internal conflicts burst into open view.
Prime Minister David Lange is depicted clutching onto a dramatically declining poll curve. In contrast, a wide-eyed Jim Bolger clings onto his ascending one, overtaking Lange, but worried about speed wobbles.
They share the same thought bubble: "Oh Dear!! How did this happen?"
The precise moment when Lange's lot lost it will be debated for a long time, as befits the greatest human and political drama in New Zealand's modern politics - as well as tragedy and, with apologies to his two immediate successors, finally farce - but Scott nailed the dramatic change of fortunes.
Prime Minister Bill English will be pleased that, if nothing else, his initial poll line has so far only vibrated, not fatally shifted for the worse like Lange's did.
But during the past week or so, everyone I've talked to who is or has been involved in politics, one way or another, felt like everything had changed in the political dynamic.
It felt the same after Don Brash's speech at Orewa. I remember his sharp intake of breath and smile watching a 17-point bounce stare back at him on the telly. Helen Clark's ascendant period ended right then, in early 2004. Sure she won another election in 2005, as New Zealand's women, mostly, weren't prepared to take a risk on Brash, but National had seized the initiative off the incumbents.
Former Minister of Finance Roger Douglas, Lange's architect, mused years later, in Marcia Russell's brilliant series Revolution, that he thought the Fourth Labour Government might win four or five terms. The star power of that Cabinet was certainly something, with Geoffrey Palmer driving the engine, Richard Prebble happy to wage battle at the front, Stan Roger clearing minefields, with David Lange all the while selling change to the public, aided by people seeing that things had to change. Mind you, Douglas said in the same documentary that while he had always understood his role, he believed that Lange should have understood and kept to his, and so instead pain followed pain instead of Douglas' dreamed-of gain.
Jim Bolger and his colleagues, during the Lange-Douglas ascendant phase, were entitled to wonder how long they might warm the opposition benches. Bolger was leader for less than two years when Lange publicly defected from his own government, so Scott's cartoon captured the wide-eyed quality of Bolger's overnight appeal.
For me, the shock poll of Brash's bounce was tempered by disrespect for the means employed to achieve it: striking a race nerve rubbed raw by the foreshore and seabed furore.
Orewa did, however, achieve what his brains trust, in and outside the party, hoped for: consolidation of the centre-right and National being perceived as back in the game. Nonetheless, it was a genuine shock for the non-politician, Don Brash, and 26 of his colleagues in Parliament, recovering from their 20.93 percent drubbing in 2002, to find themselves all of a sudden popular. Brash pushed Clark to the brink in 2005, which paved the way for renewal and success under Key in 2008.
Metiria Turei's foray into social justice projection has now, similarly, acted like a keystone that, once dislodged, precipitates a large slip. It has, according to polling so far, dramatically realigned the balance between the centre-left parties in Labour's favour and allowed leader Jacinda Ardern to open up new election possibilities for voters that seemed only two weeks ago unimaginable.
One of Labour's chief weaknesses, its leadership, is now perceived as its key strength.
A keystone disturbance suggests an unstable equilibrium of some description or another. National will be hoping it's only on the centre-left. Labour will be hoping it's something larger still. Personality, policy, and performance during the campaign will help decide that question. But Labour are back in the game, and from their position two weeks ago, that is a surprise.
A jolt to the status quo is a positive development for the country, especially as a third-term government challenges history and seeks a fourth. After three predictable, non-competitive elections, National needs to be tested and it is doubtful a 'don't put it all at risk' mantra will work for English as it worked for Clark in 2005. The times, situation and people are different.
The large bounce that Ardern has initially achieved will serve to refocus the campaign squarely on Labour and National, with Winston still smiling even as he sheds some vote share.
It suggests something else as well; if the poll direction is sustained, the rush is towards the centre, in which case the populist contagion - associated with Trump, Sanders, Brexit and Corbyn - may have found a patient already safely inoculated from its disruptive effects.
Jon Johansson specialises in political leadership and New Zealand politics at Victoria University of Wellington.