In all the hubbub of last week's leadership spill, the media establishment focused on the personalities and missed the bigger story. In the past five years, one issue has wrought more damage to the Australian political landscape than any other. It has profoundly influenced the rise and fall of both Labor prime ministers and the respective fortunes of at least the past two federal opposition leaders. That issue is climate change.

It was a factor in the end of the Howard government. It gave the man who defeated him, Rudd, a mandate for office, only for him to lose that authority when he dumped the complex trading tool he devised to solve the ''great moral, economic and environmental challenge of our age''. And it profoundly and irrevocably undermined public trust in Australia's first female prime minister. Her turn against Rudd's scheme shaped her path to power. Reversing that position broke a promise with the electorate that has invested Abbott with a mission. Whatever Rudd does next, his move on the carbon tax will have the biggest ramifications.

There are two reasons Rudd must make a move. The first is that climate is intricately linked to why he was deposed the first time. His temperament is an internal facing issue - it offended his day-to-day colleagues but the public was largely insulated. The public's problem was with his high-handedness - his eagerness to couch policy in polarising, moral terms (the Robin Hood mining tax, the moral responsibility for an emissions trading scheme) and then show himself bare when the polls deserted him. The second is that the carbon tax is petrol in the tank for Tony Abbott. Do nothing, and nothing will change. But here's the catch. If Rudd seeks to refresh the debate by delving into wonkish distinctions between a carbon tax and an emissions trading scheme, he is making the wrong move. Reappraisal needs to happen at a much higher level: why should we care about this issue at all?

In the mid-2000s I was involved in advising both sides of politics on some design implications of an Australian scheme. I am now convinced most people don't really care about these granular details. In my opinion, the real reason we argue about climate change has to do with neither science nor morality. It has to do with freedom. There are two parts to this. The first is political freedom - how free should we be as voters to decide our own environmental policy as opposed to delegating it to scientific experts? The second is economic freedom - how free should we be to live the material life we have reason to value? Unless a political leader unpacks the freedom problem and addresses it front on, they will not put this issue to bed once and for all.

The fact that we are not actually arguing about science should be self-evident. Too few of us have the scientific qualification to understand the issue from first principles. It comes down to trust - who do you choose to believe when you don't have the expertise personally, and what is their scope of authority? We need to think about climate science more like monetary policy and less like diktat. In a healthy representative democracy, we need certain limited delegations to expert scientists but we must respect the freedom of voters to decide on the fiscal implications of this. President Obama's announcement last week that he will bypass Congress to give an executive memo to the Environmental Protection Agency is a troubling development. He is at the start of a very difficult journey that will no doubt annoy the true defenders of liberal democracy.