Nearly 40 years after a Labor government first promised that no school would be worse off, another Labor administration has been forced to do the same. Julia Gillard gave the assurance to an independent schools’ conference this morning, a repetition of an undertaking forced by yet another delay in announcing the government’s final decision on the Gonski recommendations.

Every one of the players in this tawdry arena knows that Gillard had already made that promise, and that even if she hadn’t she wouldn’t dare leave even a single school “worse” off. But the history of schools funding is so noxious that Gillard could not avoid saying it, yet again.

Everyone — including the independent schools’ lobby and opposition education shadow Christopher Pyne — knows that Whitlam caved in to the Catholic bishops in 1973 when they insisted that “state aid should go to every non-government school, even the rich ones, so that henceforth and forever state aid would be acknowledged as a right not a privilege”.

They all know what happened to then-rising star Susan Ryan when in 1983, in the flush of recent election victory, she got prime minister Bob Hawke to agree that money would be taken from a handful of high-fee schools and given to the poor Catholic schools. “Ryan’s hit list” saw the end of a promising career

They all know that every government of whatever political complexion has ever since made sure that “no school will be worse off”. And they all know that Gonski was instructed by Gillard to take the “no school worse off” option which, by Gonski’s calculation, could lift government subsidies to high-fee schools from around 10% of recurrent to 20% or even 25%.

And yet, there they were last week, the independents claiming modeling to demonstrate that Gonski would leave them worse off and Pyne enthusiastically seconding their motion and, late this morning, expanding the claim to include large numbers of government schools as well. Ironically, this is exactly the kind of political juvenilia that Gonski was asked to end.

Gonski’s formula comes in two parts. First, every school, irrespective of sector, should be funded according to the size of the educational job it is asked to do. The more difficult the job, the greater the per student funding. Second, Gonski proposes that all government funding, federal and state, should be put through a single national body charged with working out the size of each school’s job and making allocations accordingly.

Gonski’s plan is so obviously sensible that few have dared to attack it head on. For Labor, Gonski’s appeal is emotional and political. It would get the damaging squabbles off the political agenda. It would differentiate Labor from the Coalition, to Labor’s advantage. And it would tackle persistent and probably growing educational inequality, core Labor business.

So why one delay after another? For a start, money is very hard to find, and Gonski requires a lot of money. The initial ask of $5.3 billion is now up to $6.5 billion and rising. Moreover, Gonski requires the states to stump up more money and agree to a national body that would take over some of their functions, not easy when the four biggest states are in hostile hands. And there is the nagging and well-justified fear that the money won’t make any real difference.

The best available calculation is that real per pupil spending on schools rose between 1964 and 2003 by 2½ times, most of it going to pay more and more teachers to put in front of smaller and smaller classes. Yet over the same period inequality has persisted, and is perhaps getting worse.

It is now absolutely clear that past a certain point, reached some decades ago, the educational payoff to smaller classes is just about zero, and that there are much better ways of spending the money, including better pay, career and study prospects for capable teachers willing to work in disadvantaged schools, peer- and cross-age tutoring, “right-sized” class groups varied according to the task at hand, technology-based learning programs, rigorous in-school teacher appraisal, mentoring and development, and technology-based student performance monitoring and analysis capacities in schools.

But will schools trade off smaller classes for options such as these? Not if the Australian Education Union has its way.

Even a fully implemented Gonski would have little control over how the money is actually spent in schools. Gillard’s reported announcement that each school will have to prepare a performance plan won’t provide much political cover against Pyne’s charge that Labor’s “education revolution” has been “a masterclass” in wasteful spending.

Another problem is that Gonski provides a funding floor but does not impose a funding ceiling. It will leave the high-fee schools to do as they have been doing ever since Karmel, taking the money then spending yet more to put plenty of daylight between themselves and the rest.

Pyne has been giving every appearance of enjoying Labor’s twists and turns on Gonski. First he claimed that they had already wasted vast sums. Then he predicted that they wouldn’t be able to find any more. Then he announced that an Abbott government would repeal any legislation giving effect to Gonski. And now he is claiming that they will diddle a few non-government schools.

Pyne might live to have some of this come back to bite him. What if Labor does find the money but his state colleagues refuse to do their share? And it’s one thing to maintain the present shonky arrangements, but quite another to revert to them after everyone has seen something better. And if reverting turns out to be too damaging, where would the money come from? Abbott’s financial back is even harder against the wall than Gillard’s.

*Dean Ashenden has been a consultant to state and federal education ministers and agencies, and was co-founder of the Good Universities Guides