On the face of it, this is a strangely Labor budget: spend up big on "nation-building" public works, raise new taxes, and slug the big banks. More Chifley or Curtin than Costello.

Key points: Bank levy applies to big four and Macquarie

Bank levy applies to big four and Macquarie Medicare levy rise to fund NDIS

Medicare levy rise to fund NDIS Path to surplus "biggest guffaw in the forecasts"

There's a levy on the big four plus Macquarie Bank — effectively a Great Big New Tax — and big new penalties for bad bank bosses; the kind of budget policies you might imagine former Labor treasurer Wayne Swan delivering, but Scott Morrison?

Then again, it's a neat way to neutralise Labor's political attack that the major banks would be the biggest beneficiaries of the Coalition's policy of cutting the corporate tax rate to 25 per cent.

The able-bodied are funding the disabled through a rise in the Medicare levy to fully fund the National Disability Insurance Scheme. There's also funding cuts for elite private schools.

It all seems so reminiscent of that old socialist principle, from each according to his (or her) ability, to each according to his need.

This might seem a little weird, until you realise the conservative gospel of fiscal policy has been tossed out the window.

For years Peter Costello, as treasurer, trained the public to accept a simple view that deficits are bad, surpluses are good.

The apotheosis of good economic management, under the Costello manual, was a government that was "debt free".

This fiscal fixation on surplus as the be-all and end-all of the budget deterred governments from investing in long-term public assets that the country sorely needed lest they be seen as poor economic managers.

It led to the silly situation where governments shunned borrowing to invest in railways, roads and other necessary infrastructure when borrowing costs were about the lowest they had ever been.

Now Mr Costello's legacy, which has dominated political discourse for more than a decade, is dead.

Infrastructure plans a fine line between nation-building and pork-barrelling

Mr Morrison has buried the ghost of past fiscal thinking with his embrace of "good debt" for long-term infrastructure investment, and "bad debt" for recurrent spending on government wages and programs.

In principle, it's not a bad thing.

In practice, there's a risk that it could become a vehicle for all kinds of boondoggles and hornswoggles.

Look at this budget and we have the holy grail of inland rail, and all manner of regional infrastructure funds. There's a fine line between nation-building public assets and pork-barrelling.

We used to have an independent body overseeing the spending in infrastructure. The fact the new infrastructure financing unit appears as if it will be overseen by the Prime Minister's Office is, on the face of it, a bit of a worry.

There's also scope for fudging now there's three measures of the budget bottom line: the Underlying Cash Balance, the Headline Cash Balance, and the Net Operating Balance — with its exquisite acronym, NOB.

Even on the old measure, the Treasurer is still promising a surplus — and as it has been for many years now, the surplus, on paper, is just four years away.

As usual, some of the assumptions about how we'll get there appear optimistic. Even heroic. Take the forecast that wages growth, at a historic low of 1.9 per cent, will soar to 3.75 per cent as we reach the next decade.

That's the biggest guffaw in the forecasts.

If wages growth does double, as forecast, take a deep breath while contemplating where mortgage interest rates might be.

If wages don't rise as predicted you can kiss goodbye to the surge in income tax receipts that's meant to get the budget into the black.

But in the new world of good debt and bad debt, will it matter anyway?