Yet the case for a mature debate is strong. Essentially, when we talk of fed/state relations, we're talking about the problem of the states having very few revenue powers and being reliant on allocations – hand-outs is the usual term in these discussions – from Canberra.

Prime Minister Tony Abbott looks askance in Parliament during Question Time. Credit:Alex Ellinghausen

The GST was meant to fix this but it only went part way due to political deals which saw major exemptions.

Collected at point of sale, it is remitted to the states but not in the proportions in which it is raised. WA gets back just 37¢ in the dollar. Smaller states get more than they raise.

Closing off exemptions would secure an extra $13 billion a year, according to research by the Grattan Institute, even allowing for 10 per cent of that to be used to compensate the poor.