National and Labour leaders show just how close it is and how much is at stake, by upping the risk factor with new policy announcements live in the second leaders debate

Bill English has taken to calling this election a drag race between the two big parties, but that doesn't do justice to the twists and turns it's already taken. Today, those two main parties added significant risk to the campaign - they're taking those corners at high speed now, as we enter the final 18 days.

It started with Steven Joyce's claim of an $11.7b hole in Labour's fiscal plan. That's a bold claim. Either Labour are numpties of a very high order or National is making a desperate and cynical play. I've read Labour's fiscal plan, but anyone who knows my School C maths marks will know I'm in no position to give a definitive answer on whether it's a valid gotcha or not.

But I note two gents who have had a proper go at explaining it: Keith Ng at The Spinoff and Bernard Hickey on Newsroom. The respective conclusions: Ng says "Ultimately, there is no missing money. The money is accounted for" while Hickey says "The short answer is that Labour is mostly right and National is mostly wrong, although there is fault on both sides. The big picture is there's certainly no fiscal crater for voters to peer into."

Hickey goes onto explain that, essentially, while National has accused Labour of not allowing for new spending year after year, Labour just had recorded that on another budget line. It's worth noting economists BERL reiterated its endorsement (albeit as a paid client who assessed the plan before it was made public).

So as we stand this morning, if this was National's 2017 attempt at "show me the money" it has fallen flat. Will people only remember the "hole" quote and not the outcome? Or will people see this as the act of a desperate and failing government?

You'd have thought the leaders may have wanted a cup of tea and a lie down after that squabble, but it was only the entree to a risky night of live television at the TV3 leaders debate.

English rolled the dice again, announcing that National would be able to "have a crack" at bringing 100,000 children out of poverty in the next term. Pressed if this was a commitment, he said yes. 

The promise is remarkable for its scale and for its timing. Labour has for much of the last nine years pressed National to measure child poverty in New Zealand and thereby institute a target. National has long refused. 

As recently as last October, John Key told RNZ's Morning Report he wouldn't back a call by Chilidren's Commissioner Andrew Becroft to get a 5-10 percent reduction in the number of kids on the material deprivation index. That figure stood at 149,000 at the time. Key said we "do the best we can" but "I don't want to put a number on it".

Why? Because the issue is "complex", it was too hard to agree on a single measure of child poverty and "you could spend a long time agreeing on one particular target", but it was better to offer a range of initatives such as cheaper doctors' visits and breakfasts in schools.

It seems all those reservations and complexities have disappeared. A year ago a single measure was too hard. Now, 18 days from an election, a measure and a target can be discovered in a single election debate. And the target is vastly ambitious.

This could be the "something new" National has been looking for to show it's not a tired government that has lost its sense of purpose. Certainly, English out-passioned Ardern in the debate when it came to child poverty. He literally went up on his toes, his face came to life and he was fired up. Ardern meanwhile remained her measured self.

But it's risky because it's a move - clearly a calculated one - that could backfire. Voters may embrace the heart, or they could see it as deeply cynical. As too little, too late. Sometimes, it's worse to look tokenistic or late on such a profound issue than to do nothing at all. It could anger voters and feel like playing politics. So it's a punt.

His opponent had her own risky moments though. Jacinda Ardern promised to resign rather than raise the eligibility age for superannuation. English not unreasonably - if hypocritically - called that a betrayal of her generation. It's a cynical calculation from a party that at the last election was promising the exact opposite, with Ardern's support.

Ardern also threatened a rights war with Australia, if they kept taking rights off New Zealanders living there. Specifically, she said if they moved to lock New Zealanders out of tertiary education over there, we'd do the same to Australians here.

On any other day, a new poverty target and a slap down of Australia would be massive stories on their own. Today, they're competing for oxygen.

The other electric moment in the debate was over abortion. Catholic Bill English said he was happy with abortion law as it is; Ardern said she wanted it taken out of the Crimes Act. It's a clear symbolic line between the older man and the younger woman. Indeed, the young woman sitting across from us at the debate lit up at that moment.

It could be an issue that motivates turnout. But that too comes with risk. Labour's Pacific vote will be troubled by that stance, for example.

The best moments? English finished upbeat, but is best line was when asked why New Zealand should vote for him when they didn't back in 1992. What's changed? He said "I got back up again". That was a strong answer.

Ardern, asked why New Zealand should vote for her given she's never been in government, said because she stood for generational change and a vision for New Zealand. It was a well-worn line, but again, looking at the audience, you can see how it's working.

English's hardest job is shaking off the sense that, as Ardern said to him, it's time for him to hand over the reins. He's had his turn and a new approach is needed. She stands for that without saying a word, and that's hard for him to combat after nine years.

But hard as it may be, he's giving it a fair crack. He's rolled the dice and taken the risk. As Paddy Gower kept saying in the build-up to tonight's debate, there couldn't be more at stake. With big stakes, come big risks. And a very big campaign.