Now that Labour has released its fiscal plan, we can compare the two main parties' offerings.
The main differences relate to tax, the treatment of what remains in the Covid-19 Response and Recovery Fund, and operating allowances, which is how much new money is on the table for the next three Budgets.
You would normally expect the centre-right party, National, to be the more conservative and fiscally prudent of the two. Not this time.
Over the four years to June 2024 — the period covered by Treasury's pre-election forecasts and which includes the three Budgets that whoever we elect this month can expect to write — there is a $10 billion difference between the two parties' expectations on tax.
The difference is mainly National's plan to forgo $8.2b of revenue, largely as a result of temporary increases in income tax thresholds, plus some accelerated depreciation and landlord-friendly changes.
Labour plans no changes, apart from a new top marginal tax rate of 39 per cent applying to incomes over $180,000, and beginning to nibble at the exorbitant advantages the digital behemoths enjoy. It expects to rake in an extra $1.9b over the forecast period.
National is selling its 16 months of income tax cuts as a stimulus package, aimed at hardworking New Zealanders on the average wage. This is specious.
The distribution of the tax cut looks quite a bit different when you line it up against a helpful table the Treasury publishes with each Budget. It breaks down the working age population — in this case everyone aged 16 or older — into income bands $10,000 wide and estimates how many people are in each band.
Someone on the average wage (based on average weekly earnings from Statistics NZ's quarterly employment survey) earns $65,00 a year. But that puts them in the top quarter of the income distribution (people ranked by income).
The lion's share of the tax cuts would go to the 25 per cent of the population earning the average wage or more, who pay most of the income tax.
There are just as many people in the bottom quartile of the distribution who will get nothing from either party because their incomes fall below the current lowest threshold of $14,000 and so will gain nothing from hoisting it up to $20,000.
Importantly, another 1.5 million people have an income between $14,000 and $48,000. They get an extra $8.10 a week for 16 months under National's policy.
That group, which comprises just under 40 per cent of the working age population, includes anyone working 40 hours a week on the minimum wage.
It includes anyone depending entirely on New Zealand Superannuation.
And it includes anyone at the median income from all sources, as measured by the household labour force survey (income).
The median wage earner earns $10,000 less than someone on the average wage. He or she would get a tax cut of $25 a week, or only half as big a cut as someone on the average wage.
If the objective of this fiscal largesse really were to stimulate spending, it would not be concentrated on the best-off quarter of the population.
Instead, it would focus on those more likely to spend every extra dollar that comes their way, rather than, say, knocking $3000 off the mortgage. The design of the tax cuts looks more political than economic.
National is entitled to respond that even $8.10 a week is $8.10 more than people will get under Labour's policy.
Labour's emphasis on "stability and certainty" means it will not use the powerful lever of taxation to address inequality (except very marginally) or productivity stunted by a tax system which discourages saving in a capital-shallow economy and encourages borrowing for housing instead. It invites criticism along the lines "if not now, when? If not you, who?"
The second major difference between the two big parties relates to the treatment of the Covid fund, the $50b Parliament has authorised the Government to borrow to respond to the pandemic. As at the time of the pre-election economic and fiscal update (Prefu) last month, there was still $14.1b left unspent.
Labour has committed $2b of that, primarily ($1.5b) to extending the small business cashflow loan scheme, leaving $12.1b available in case of resurgence of the pandemic and perhaps to buy vaccines.
Should the remainder of the Covid-19 contingency not be required, it says, net core Crown debt would remain lower across the projection period to 2033/34, compared to the track in Prefu which assumes all $50b will be spent.
National, for its part, has earmarked $4.6b of the fund for tax cuts, leaving $2.6b less than Labour in the kitty should viral calamity strike again.
To state the obvious but often glossed-over, when the Government is spending more than its income, tax cuts and spending increases both add to the deficit and therefore the amount of debt which future taxpayers will have to service.
On the spending side, the big difference between the two parties' plans relates to the operating allowances, which is the pot of new money ministers fight for in each Budget round.
The allowances have to cover both new initiatives and inevitable cost increases to existing baselines.
For example, health spending has increased by $6b over the past six years, yet the Prefu forecasts have it flatlining at $21b a year for the next three Budgets. In the face of a growing and ageing population and normal inflation, that would represent a real per capita fall in health spending. In practice, health gets the lion's share of the new money in any Budget.
Labour's fiscal plan increases the operating allowance for the next three Budgets from $2.4b to $2.625b, enabled by the extra tax it expects to raise.
National, by contrast, plans to cut the operating allowance to $1.5b in next year's Budget, and to $1.8b in the following two.
The cumulative difference over the next three years between the two parties is $5.85b. Both parties have already committed to spending an additional $2.9b over the forecast period on normal, non-Covid things.
Labour has promised another $1.2b for education and $700 million for health. National's big-ticket items are an extra $700m for education, $500m for health and $900m for its package targeting a child's first 1000 days.
National has also identified $450m a year in savings from existing spending, chiefly axing the fees-free programme, which it regards as middle class welfare.
Even so, with its lower operating allowances National has left itself only $5.5b of unallocated new spending altogether over the next three Budgets, most of it ($3.9b) in the third year, 2023/24. That is in the context of operating spending which exceeds $100b a year.
Labour, by contrast, has $12.9b of unallocated new spending over the next three years. It also has $2.6b more than National left in the Covid fund.
It is pretty clear which party expects to have to deliver on its fiscal plan.