Many fingers will inevitably point toward leader Judith Collins.
Collins' first message to her MPs after her defeat was that the party needed to return to its former state of discipline and stability. That may prove very hard to do.
Collins returns to Parliament with a much smaller caucus – down from 54 to 35 - but it is not necessarily a more united one.
Collins herself was quick to rule out any suggestion she would step down as leader, saying stability and certainty were what was required – not yet another leadership change.
However, it is rare thing for a leader to survive such a plummet in an election.
Collins delivered the second worst result in National's history. National's result was close to the 25 per cent Labour got in 2014 under David Cunliffe. Cunliffe barely lasted a day.
In normal circumstances, the same would be true of Collins.
However, Collins' defeat was very different to Cunliffe's. She had just three months in the job, she was not wildly unpopular with National voters, and she had the job of Sisyphus to do.
She was trying to drag the National Party up a mountain while beset by Covid-19, rogue MPs, a bitter and disastrous leadership change before hers, a massively popular opponent, and in the final days, a foolhardy leak by one of her own MPs about a caucus disagreement.
Those are valid reasons rather than excuses for Collins, and some were out of her control.
That is enough to ensure Collins does not face any immediate challenge for the leadership, but that does not mean she will last until 2023.
The caucus will also expect a bit more of a show of contrition than Collins offered in her press conference the day after the election.
In that, she put the loss down to the adversity she faced rather than anything she had or had not done. Every leader must take some responsibility for a defeat, regardless of mitigating circumstances.
In short, National could not get traction on its promises, or its attacks. And it could not counter Labour's messages about National's lack of stability.
Collins and campaign chair Gerry Brownlee will come under the spotlight for that.
Brownlee, who will be stinging after losing his supposedly safe Ilam seat, is now considering his future.
But there is a case to be made for him staying in Parliament. Even his detractors see his experience as having value: not least in dealing with Speaker Trevor Mallard, who could easily push around a 35-strong team in a way he could not do with a 54-strong team.
Collins herself is unlikely to face any immediate challenge. That is not because of gratitude or a fondness for Collins, but rather out of self-interest by the potential contenders.
Ardern's historic result will inevitably result in a honeymoon period. Far better to bide one's time until some things start to resemble custard.
National's "review" will not be pleasant, and no new leader would want to deal with the fallout from it.
As one MP said "nobody would want [the job]. Let them stew in their own juices for a while."
But there are potential contenders waiting and watching.
In the last two days, Simon Bridges and Mark Mitchell have both ruled out a challenge – but such promises have flexible expiration dates.
Christopher Luxon will be in the frame at some future point. Nicola Willis and Chris Bishop could also be starting to consider their futures.
2023 will remain a massive challenge for National. But there is some hope for it in the Cunliffe comparison – and Ardern will also have that in her mind.
In 2014, Labour went back into Parliament with just 32 MPs. Three years and two leaders later, Jacinda Ardern became Prime Minister.
