TONIGHT'S budget will be an entirely political document like no other in recent years, in a way that utterly exposes the emptiness of both the prime minister and his treasurer.

Now that might seem to be a statement of the bleeding obvious. Surely all budgets are political. They are after all put together and delivered by, well, politicians.

Indeed further, by definition, a budget just before an election like this one has to be at least partly directed at the, well, coming election.

So why do I say this is political like no other in recent years? Because some of the - indeed, all the - big decisions have been taken purely to get particular numbers in the budget papers.

Again this happens all the time. You cut or increase, say, health spending with an eye to the bottom line, you don't cut taxes to avoid sending the budget into deficit, and so on.

What makes this budget different - a return in some senses to a 'Paul Keating future' - is that some key decisions have been taken entirely to achieve a numerical outcome in the budget papers in a way utterly disconnected to anything of substance.

There are two big ones: the resources rent tax (RRT) , or as it is dishonestly titled, the resources super profits tax; and the ditching of the emissions trading scheme (ETS).

The RRT was unveiled a week ago. The question that hasn't really been asked, and so therefore not answered, is: Why?

The government had the (Ken) Henry tax review for nearly six months. Why was it necessary to rush it out a week before the budget? And then, not simply table the review but deliver the government's complete if very minimal response to it?

Nothing in the exercise was time sensitive - the big changes were/are going to start years into the future. It wasn't a beer and cigs exercise where the higher rates applied immediately.

The answer is very simple. By making the RRT in particular 'official policy', the money it raised, the money it is expected by Treasury to raise, will be included in tonight's figures.

It is not petty cash. The RRT will raise $3 billion in 2012-13 and $9 billion in 2013-14 - the last two years covered by the official budget forecasts.

So purely in order to be able to include $12 billion of (projected) revenue in the budget papers, Kevin 'Gougher' Rudd and Wayne 'Riskless' Swan, were prepared to deceive the resources industry and risk seriously damaging the nation by sowing genuine fear.

The sensible, the grown-up, thing to do would have been to unveil the proposed RRT, subject to discussion. But then, the money could not have been included in tonight's budget.

That alone shows both are unfit to continue in their roles. That they would so wilfully place budget form over policy substance to the nation's potential detriment.

Then there's the ETS. Again, why was it necessary to formally abandon it just before this budget? For exactly the same reason? Once formally abandoned, the ETS numbers come out of the budget.

Now with the ETS they come out of both sides of the budget. Both the money expected to be raised by the tax and the money handed out in compensation.

So if formally ending it is budget neutral, why do it?

The answer is even more damning of Rudd and Swan - and also a very big warning to anyone who believes they have really abandoned it.

It is all about only the one side - the spending side. Removing the compensation - totally artificially - cuts spending by over $10 billion a year from 2012-13.

But if it also removes a similar sum from the revenue side, what's the point?

The answer is that it enables the government to deliver on its promise to keep spending growth to 2 per cent year.

So we have a prime minister who welches on "our greatest moral challenge" purely - sorry, only - to meet a completely artificial budget number. And an utterly meaningless number at that.

A third big decision doesn't produce quite this sort of empty fiscal chicanery, but comes close; and also shows the aimless deviousness of our current 'leaders'. It's the NBN - the National Broadband Network.

Finance Minister Lindsay Tanner was gloating the other day that the opposition couldn't 'save' the $43 billion earmarked for the NBN by cancelling it, because it was an 'investment' by the government and so not in the budget 'spending numbers'.

Again that's a sterile, utterly childish but potentially seriously damaging exercise in fiscal form over substance.

Of course, we would save $43 billion of real money if we abandoned the utter waste and stupidity of the NBN.

In Tanner's world, don't worry about the waste of real taxpayer money, just focus on the artificial numbers in a budget.

Tonight we will get a hollow document from a cabinet of hollow children. To think there was a time when we had grown-ups running the country.

Originally published as Budget to get a big poli-tick