Key Points:

If John Key's demeanour and language seemed to have more than a slight touch of the prime ministerial yesterday, it was all deliberate on National's part.

Cometh the crisis, cometh the man was the sub-text of the four-page statement which Key issued as a considered response to Treasury's pre-election economic and fiscal update released the previous day.

It was intended to convey not just the impression of prime minister-in-waiting, but of prime minister full stop.

The shocking figures in Monday's update may have given National a big headache by forcing a last-minute rejig of its tax policy.

But National strategists realised the update was so gloomy and so negative for Labour that it gave National the opportunity to nail this election once and for all.

And it handed Key the opportunity to get on the front foot.

Yesterday, National grabbed these opportunities with both hands.

The update is a Treasury document and is therefore regarded as independent. But the name on the cover was Michael Cullen.

The ugly numbers are down to international circumstances. They are not the finance minister's fault. But the update is so full of bad news that National is punting it will hang around Cullen's neck through this campaign like the albatross around the neck of the Ancient Mariner.

Meanwhile, National today intends to silence Cullen's non-stop questioning of the affordability of its tax cuts when Key and Bill English unveil a scaled-back plan.

It will reduce planned cuts for the better-off to bolster the amounts for those on the average wage.

This is good politics as the well-off can hardly complain about making a small sacrifice for the sake of the country's straitened accounts.

National cannot afford to disappoint the lower-earners, - especially as it is planning to withdraw some entitlements from the 800,000 people signed up to KiwiSaver.

National was going to detail and explain the changes to KiwiSaver yesterday. But bad weather stopped Key getting from Auckland to Wellington.

However, National had to make some response to the fiscal update. It also needed to adjust people's expectations about today's tax package.

Its answer was to go on the offensive for the first time in the campaign, saying the update's forecast of a "decade of deficits" was final proof Labour was a spent force.

National is being careful to avoid doing anything which could enable Labour to accuse it of exacerbating economic jitters.

As it may be picking up the pieces after the election, National has nothing to gain from shattering confidence in the financial system.

But it does not have to do much. The contents of the Treasury update speak for themselves.

National's intention yesterday was to present Key as a safe pair of hands when it comes to responding to a mounting economic crisis.

But yesterday was only a preliminary round. Today is the day the numbers must add up for National. On Monday, Labour's hold on the crown of economic management slipped; today is the making or breaking of National's efforts to take that crown.