Debate over Gonski and schools has ballooned into a bidding war between Julia Gillard and Tony Abbott. And with that the focus has shifted from how to spend the money to where it will come from.

Gonski asked for an extra $5.3 billion, not a small figure when the total spend on schools is about $45 billion, and it’s growing fast.

Last week, spooked by the independent schools lobby, Gillard zoomed past her earlier no-losers promise to guarantee that every independent school would be better off. That will not come cheap. Even a no-losers clause would push the government share of independent school funding up from about 10% of recurrent to as much as 25%, so where would an “everyone wins” formula take us?

But there’s more. If Gillard is to deliver an improved relative position for the thousands of schools doing the hard yards, as recommended by Gonski, a multiplier comes into play. More at the top means a lot more for the bottom.

Pushing the bill up yet again is the fact that the government still has to persuade the states to put their hands in their pockets. Gillard has now put the government in a weak bargaining position.

Perhaps the only comfort for Gillard is that Abbott has been forced into competing with her spending, and, quite possibly painting himself into a corner in the process. Rejecting Gonski on grounds including cost, Abbott almost immediately turned around to promise funding increases over current levels of no less than 6% every year for the next four years.

What the government has let itself in for is still anyone’s guess; its estimates are still weeks away. In the meantime Abbott’s spend is probably smaller, but his purse is smaller too. He needs to find many tens of billions in savings to pay for terminating the carbon and mining taxes, among other things.

It probably doesn’t matter who’s in bigger trouble, because in the course of last week’s short, sharp auction, both sides have made promises they can’t keep, unless they can find new money.

There are four places to look, ranging from the familiar to the unheard of.

The first has been floated by Ben Eltham at New Matilda. Eltham quotes Treasury Secretary Martin Parkinson’s insistence that we need “more revenue or significant savings”, and plumps for the former. Eltham argues that taxes are lower now than under Howard, that Australian government takes a smaller share of the total economy than it did in the 1990s, and that our government sector is one of the smallest in the OECD. Eltham wants every tax revenue option back on the table: income tax, GST, negative gearing, superannuation, capital gains, the lot.

A second suggestion has been floated in The Australian Financial Review by veteran journalist Brian Toohey. Why not dip into the Future Fund? Toohey argues that more and better spending on schools is an investment, not an expenditure, and therefore an appropriate use of the fund. If it switched to “plain vanilla” investments in the local market (term deposits, government securities and corporate bonds), Toohey argues, its annual income would cover most of Gonski’s cost.

A third option has been canvassed by higher-education commentator Gavin Moodie, although he had other purposes in mind. Moodie has suggested that parents paying school fees could get HECS-like income-contingent loans that would allow them to defer paying school fees while they have other big outlays such as mortgages. This easier access to non-government schooling might reduce numbers in government schools, which would in turn free up government funds for re-allocation.

Any impact from such a scheme would start small and grow slowly, however — unless all parents paid fees, or at least all who can afford to. And that is the fourth option, hitherto unheard of, so far as I know.

There is more to be said for and against the idea than can be said here. For those who recoil, remember that the present scheme of things demands that some parents pay while most do not, even though the rationale for this discrimination has long since disappeared into the mists of a sectarian past. One third of parents currently kick in almost $7 billion towards the annual schooling bill. They’re entitled to ask: what about the rest of you?

Each of these four options, or any combination of them, comes with its own mix of pros and cons. None, apart perhaps from Toohey’s suggestion, could be introduced quickly, and even that would expose the government on yet another front. Anyone got a better idea? If not, Gonski looks to be a goner.

Gonski is no silver bullet. It guarantees very little. But it makes much possible, and has become an important test of faith and intentions. It has attracted widespread support, including the support of many on the non-Labor side of politics.

The states are an obvious obstacle. Several are driving a hard anti-Labor, states-rights bargain; one or two may pull the pin. But only real opposition to the basic idea has come from the independent school sector through its cat’s paw the federal opposition. They have precipitated yet another juvenile, grasping squabble of the kind that, ironically enough, Gonski is designed to end.

Adrian Piccolo, education minister in the NSW (Liberal) government puts it with commendable candour: “I think everybody actually knows what the right thing to do is. The greatest problem here is overcoming the politics … I think it’s terrible.”

*Dean Ashenden has been a consultant to state and national education agencies and ministers of education. He has written on a range of education issues in academic, professional and the mass media.