Politics is a numbers game. Numbers determine all sorts of things: whether a party makes it into Parliament in the first place, whether a party gets to govern, whether they're successful with legislation and in terms of this argument, whether they have the numbers to lead.
If you can't count then you should steer clear of politics.
Business leaders in a survey say National should have a leadership succession plan. They of all people should know about numbers and they should also know that in politics the idea of a successor being anointed by a leader is virtually unheard of.
Think about it, David Lange wasn't even in Parliament when Bill Rowling became Prime Minister on the death of Big Norm Kirk. And Rowling fought three elections before Lange managed the numbers to roll him. To be fair, he won more votes than National in his final two elections, but numbers in those days weren't as important, in terms of votes cast, as they are today under MMP.
There was no succession plan when Rob Muldoon clung on to power after the schnapps election in 1984. He certainly wasn't happy about being rolled by Jim McLay, which was evidenced when he was asked whether he was going to be a thorn in National's side and he said, no, he was going to be a prick.
The closest Labour came to a succession plan was when Lange resigned and Geoffrey Palmer moved on to the ninth floor of the Beehive. There was certainly no plan in place though when Mike Moore shoved Palmer aside eight weeks out from the 1990 election.
And Jim Bolger never contemplated Jenny Shipley becoming the first female Prime Minister of the country when she did the numbers while he was downing aperitifs in Paris.
But Helen Clark was a mathematician compared to the rest of them. She carefully did the numbers when she rolled Mike Moore and was at it again when her own colleagues tried to shaft her a few years into her leadership. She hung on and became Prime Minister until the public did the numbers on her.
There was certainly no succession plan for Labour after her departure - Phil Goff, David Shearer and David Cunliffe would attest to that.
Similarly there's no succession plan for Teflon John Key, who has no intention of moving aside for anyone and the business leaders don't want him to at the moment either.
But there's one thing certain in politics, the day a leader's elected is the day his or her number's up!