So, Victoria can no longer demand that owners of electric vehicles take snap shots of their odometers each year and pay a tax according to the kilometres travelled. Two quixotic EV motorists appear to have won a victory for the environment in a High Court fight similar to that in the iconic movie The Castle. But there is a deeper and much more important story here. It is not that Victoria cannot impose such a tax, but that ONLY the Commonwealth can impose such a tax - and not only in relation to electric vehicles (ZLEVs as they are called), but to a sweeping array of taxes. Here are the words of the three High Court judges which were adopted by a fourth to make up the majority: "Any tax on ZLEVs or any other goods - whether imposed at the stage of their importation into Australia or production or manufacture in Australia or at any subsequent stage in their distribution, sale, ownership, control, use, resale, reuse or destruction in Australia or export from Australia - can be imposed only by uniform national legislation". Everyone imagined that Victoria's ZLEV levy was a reasonable charge for road usage - for roads that Victoria had provided. A bit like a road toll. No, said the High Court, it was a tax on the consumption of the ZLEV by the owner. You could almost visualise the owner eating the battery and being taxed on every bite. As the owner "consumed" the electric vehicle the state was imposing an unconstitutional "excise" tax on that consumption, the High Court's reasoning went. The founding fathers said that only the Commonwealth could impose "excise" taxes. Otherwise, the states could get up to all sorts of mischief to impede the aim of a uniform economic Australia. The question that has dogged the court and governments for 123 years until now is: what precisely is an "excise". In the past, artful state governments got away with tricks like imposing licence fees on sellers of alcohol, tobacco and petrol according to how much they sold the previous month or year. For a time, the High Court allowed this artifice as a "licence" fee not an "excise". Last week's new definition swept all that rubbish aside and made it plain that Australia had a national economy and taxation law had to reflect that. It was a difficult 4-3 decision. It took 132,000 words. But Australians can feel completely confident that in our High Court, unlike the US Supreme Court which is little more than a dysfunctional politically internecine basket case, the judges apply legal and constitutional principle objectively to the facts. And, if a similar case arises again, the three judges in the minority in this case will not stick to some MAGA political agenda as in the US, but will apply the precedent of the majority this case. This brings us to the political consequences of the decision. And bear in mind that our High Court is non-political and made no mention of this. But it is important. The very word "tax" causes politicians to turn spineless. Too many governments and oppositions have lost government (or nearly lost government) because of tax. Think John Hewson, John Howard, and Bill Shorten. If a political leader can paint their political opponents as the imposers of a great big scary tax, they - along with their backers - will do so, until the opponents lose an election or the new tax proposal is dropped, like Kevin's Rudd's resource tax. MORE CRISPIN HULL: So, for the past nearly quarter century federal political leaders have, by-and-large, only ever cut taxes and failed to move our tax base as circumstances require. (The only exception has been a start on the laudable chasing down of multi-nationals who use off-shore tax havens, which voters almost universally applaud for the selfish reason that they think it will mean a lower tax burden for themselves.) We have seen an unreformed GST shrink in the face of consumption moving more to health and education which are exempt. We have seen financiers flock distortingly to investments in tax write-offs. And so on. Australia's overall level of tax revenue, now at 28.5 per cent of GDP, is one of the lowest in the developed world. The OECD average is 33.5 per cent, or about a third. If we moved to that average, we would raise more than $100 billion a year. The High Court's decision should be a catalyst for a total tax rethink. Before long the whole fleet will be electric and fuel-tax revenue will not be enough to pay for roads. They do not pay for all road spending now. It can only get worse. Obviously, EVs should attract much less tax than fossil vehicles. They might do similar road damage and require similar road upgrades, but they do not incur other environmental costs like pollution and extra global heating. But some form of road-use charge will be needed, and it will have to be a national one. The High Court says so. If the states want to raise revenue for roads or anything else, they will have to turn to a constitutionally valid tax: death duties, estate and wealth taxes come to mind. COVID, climate change, stagnant productivity, electrification, and an ageing population cry out for extra revenue to repair budget deficits and improve health, education and infrastructure. We have to expunge the mindset that public spending is wasteful. To the contrary, it carries with it enormous economies of scale. But out there, a lot of selfish, nasty right-wing think tanks and pressure groups have a lot of money to spend on propaganda, especially through social media, that poisons many people's opinions against government and against their own interests for the benefit of the wealthy few. The two Victorian ZLEV "heroes" only won a skirmish. The big tax battle is yet to be fought.