At the other extreme, Key clearly saw Cunliffe's capital gains tax trip-up as a cautionary tale.
Determined not to let his opponent get one back on him, he produced a tax policy almost completely bereft of details. Then he produced a defence policy which consisted of saying nothing will change. Explaining is losing, and details require explaining so best not have any. This resulted in a curious exhibition of Cunliffe criticising Key for the lack of details in his policy, criticising the media for failing to ask Key about the details of that same undetailed policy, and then criticising them for having the nerve to ask him about the details of Labour's policies.
There are other examples of schoolyardish one-upmanship. Key has tried to infiltrate Labour's heartland in South Auckland on the campaign, probably more to rile his opponent than for any real gain. Asked about it, Cunliffe said he would get his own back by campaigning in Remuera. The residents of Remuera no doubt rushed to get the bunting ready. They are still waiting.
There is also the one-upmanship over the number of support parties each leader is willing to take on board. For most people, the more friends you have the merrier. But elections are a fight to have as few as possible. Key adopted a five-party approach, based on need more than want when it came to the Conservatives and NZ First. Cunliffe tried to one-up him with his "three parties max" rule, ruling both Internet-Mana and the Maori Party out of contention. It sounded suspiciously spur-of-the-moment. Ruling out the Maori Party certainly seemed to catch a number of his own MPs by surprise. It also seemed a rather unnecessary slight. The parties responded by saying Labour clearly wasn't interested in Maori. Actor Taika Waititi, who has whanau in Mana and the Maori Party, tweeted about it, ending by saying of Cunliffe: "you ning-nong."
It also came as a surprise to NZ First leader Winston Peters who huffed and puffed about the presumptuousness of including NZ First.
Trying to explain it, Cunliffe talked himself into a hole. Having put up his hypothetical government he was asked about all manner of other hypotheticals. What if NZ First refused to play ball? How could he draft in a substitute third party having ruled out all of his spares in advance? What if he found he needed a fourth after all? Would he opt for Opposition again rather than go back on his position?
Cunliffe had clearly calculated Key's depiction of a future Labour government as an unstable, multi-wheeled affair was having the desired effect of putting people off Labour. The "three parties max" guarantee was aimed at blunting that. Unfortunately, he forgot a few minor details.
Ruling out a possible coalition partner is a luxury. Even Key hasn't dared do it this time after ruling out NZ First in 2008 and 2011. He could afford to do so then - the chances Key would need Peters' support were almost nil. On current polling, the chances Labour and its two preferred parties will be able to form a government without a fellow traveller are almost as low.
Cunliffe had his reasons but they could well give him a tricky choice on September 21. His first act as Prime Minister could be breaking a promise, or he could watch his chances of becoming Prime Minister vanish altogether for the sake of keeping one. Details, schmetails.
