OPINION: Two years ago this week John Key sent shockwaves through the country by announcing his retirement.
Key offered up as an explanation the need for change and renewal – but mostly he was surprisingly honest that he just didn't have another election in him.
Key had also judged that at some point soon the country would be ready to move on from National.
He loved winning too much to let that be the last word on his prime ministership.
The big unknowns are whether that time would have come at the last election or the next one, and the extent to which the cult of Key would have neutralised Jacinda-mania.
Loyalty to Key's economic legacy may have countered some of the mood for change for which Ardern's leadership was a lightning rod.
But these aren't questions National will be bothering itself with these days.
After an extraordinary, and turbulent, few months there are more brutal calculations to be made – such as whether Simon Bridges can carry them back into power. And if the answer is no – which seems to be the growing consensus – can anyone else do better.
This is what Bridges' MPs will be weighing up between now and February.
Does it matter if Bridges isn't popular?
Yes of course. Politics is a popularity contest, after all.
It's not just about being liked. Trust is what sells a party's policies.
When Andrew Little talked about Labour's welfare policy, voters heard "hand-out". When Ardern talked about the same thing, voters heard empathy and the language of a caring society.
While polls are thin on the ground these days, Bridges seems to be rating even worse than Little, Phil Goff or David Shearer did – presumably all useful benchmarks for judging the right time to mount a leadership coup.
Bridges is smart, articulate and personable. But he looks and sounds like a politician, in an age where voters look for authenticity.
He argues that Jim Bolger and Helen Clark weren't popular in Opposition either but went on to win and hold power for three terms apiece.
But the history books are littered with many more bodies of those who were just as unpopular as Bridges and never made it.
And besides, the world has changed vastly.
It has been nearly 20 years since Clark was elected prime minister. She predated iPhones, Facebook, Twitter, Instagram, YouTube, the advents of 24/7 news and the 24/7 politician.
So much visibility means good qualities are amplified – but bad qualities are exaggerated.
The job of Opposition is of course to oppose. But doing so while giving hope that you offer something better? That's the hard bit.
Key nailed it. Ardern nailed it. Bridges is running out of time to nail it.
Can Bridges turn things around?
Everyone knows being Opposition leader is the worst job in politics. And leading the Opposition off the back of nine years in power is a suicide mission.
But Bridges' first months in the job were marked by a remarkable confidence that this time was different. National were acting like the All Black team that scored the most tries but lost to a rival who won on penalties thanks to bad refereeing.
But lately reality seems to be settling in and Bridges is acting like a cornered man. The drawbridges are up and he is blaming some of the media for his negative image. The "soft" media seems to have gone, in place of an angrier and harder edge.
Some of this may also be strategic. Creating a mood for change in just three years is a big ask.
But National will see a window to rock confidence in Ardern and her Government in that period by being hugely disruptive, and playing to the politics of anger and conflict rather than aspiration.
Why roll Bridges when National is still polling around the same as Labour?
It's true that National hasn't plumbed anywhere near the depths that Labour sank to in Opposition.
But that's in large part thanks to the legacy Key bequeathed them. That has been a blessing and a curse. It has kept National in a holding pattern, fearful of squandering any goodwill from the Key/Bill English years. And that has delayed the painful process of change and reinvention that Opposition offers.
The anonymous white-anting of Bridges by someone who claims to be an MP is a sign that there are those within the caucus who are impatient for the debate over National's heart and soul to begin.
Meanwhile, there are other worries. Key may have gifted National many things, but a coalition ally was not one of them.
Can Bridges do a deal with NZ First or, for that matter, the Greens? On current evidence, neither.
His strategy appears to be the same as the strategy National employed at the last election. Kill them both.
Will rolling Bridges play badly with voters?
Voters punish disunity, and disloyalty is toxic. But the right leader can change everything. Ardern replaced Little just weeks out from the election and Labour's support soared.
Don Brash rolled English in an extraordinarily messy coup and nearly won an election.
Key replaced Brash after yet more caucus splits and divisions and led National into its golden years.
Phil Goff replaced Clark in an entirely amicable leadership contest and dive-bombed.
In other words, there is no right answer to that question.
If they roll him, when?
It's probably too late in the year to move against Bridges now (though never say never). So if National is serious about change, it will probably move early next year, once its MPs have taken soundings from their local electorate members and the barbecue-and-beers set.
If not Bridges, who?
Judith Collins is nudging Bridges in the preferred prime minister stakes. That's usually the death knell.
Collins is polarising and you could count the number of votes she got in the last leadership contest on one hand.
But those poll numbers will be compelling to the caucus. And Collins has done a lot to rehabilitate herself with her colleagues. There is said to be growing momentum behind her.
Deputy Paula Bennett did not put her hand up in the last leadership contest but may be another contender; her favourability ratings are said to be significantly higher than Bridges', which may explain her recent visibility.
Former leadership contender Amy Adams has done herself no favours in the finance portfolio and is now discounted.
But former police dog handler Mark Mitchell has risen in stature and is among the coterie of front-bench MPs who have kept their Government counterparts under the cosh.
Long shots include climate change spokesman Todd Muller, a former corporate high flier who is respected on both sides of the House. But there are parallels with former Labour leader David Shearer, so he might be wise to sit this one out.
Likewise rising star Nicola Willis, who is increasingly being talked up as leadership potential.
Will National do it?
When Bridges became leader it was assumed the chances of his making it to the election were slim. It's the way the cycle works. But those chances are getting slimmer all the time.
What could save him? It's a cliche, but the next election will be Labour's to lose, not National's to win.
If Labour is rocked by scandal, gets too far ahead of the electorate on welfare or industrial relations reforms, and continues to look incompetent over decisions like the Karel Sroubek affair, voters will turn away.
But it may be the next National leader who profits, not Bridges.
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