Imagine a world where every policy a government produces has to pass one of two tests to get implemented. The first test is to convince its political enemy and only real political competition to agree with any given policy, the second test is to get three disparate groups to agree with any given policy, but where two of them are usually engaged in outright warfare with each other as their respective constituencies come from literally opposite ends of the ideological spectrum.

Now imagine in such a world if the government proposed an Emissions Trading Scheme — what do you think the chances would be of that government getting any given level of emissions reduction to pass one of those two tests? Unfortunately this world happens to be the one we live in, and the probabilities of passing either of those tests look a little like this:

For the government to pass the minor party test, it becomes an exercise in herding cats, where Fielding – that Coalition sheep in sheep’s clothing — and the Greens aren’t even in the same universe with emissions trading, let alone the same argument.

Fielding’s constituency stops on emissions trading before the Green’s constituency really begins. When you get the absurd situation where Nick Xenophon is the calmest, most rational person in the room, even in the middle of one of his publicity stunts — well, you know that test is doomed to become an epic failure. Does anybody honestly believe that Fielding and the Greens would agree on a target?

That leaves the alternative test for the government — getting the Coalition to play ball.

The Coalition is caught in a bind with their twin support bases that usually have more to disagree about than they share in common, and where opinion ranges from supporting infinitely expanded levels of emissions through to moderate reductions. Yet with overwhelming public support for some form of emissions reduction to become a reality, the Coalition are more likely to pass a very moderate target level that allows them to straddle their own conflicting constituencies than either a large target which alienates their conservative base, or no target at all which alienates everyone else.

Politics is the art of the doable — it’s dirty, and gritty and often unpleasant involving trade offs that ought not to be and promises than never should be. But for any policy to become a reality it has to pass one of those tests — this isn’t an ideal world and one of those tests isn’t remotely viable.

There’s been a lot of exaggerated piffle going on in the last 24 hours over how Australia’s low initial target will not only destroy the Great Barrier Reef and the Murray Darling, but will derail any progress on an international agreement — which is nice if you’re into thinking that the world revolves around Australia. But even using that very same delusional yardstick — imagine the derailing that would have been done if no domestic target passed the Senate at all, as that is the political reality of proposing 25%+ cuts.

Too many of us seem to forget that we not only get the government we vote for, we get the Senate we vote for as well. Whatever comes out of the process that starts at Copenhagen is far more important than what happens here — we’ll be a slave to that process and won’t be the only nation taking low ambit emissions reduction claims into the negotiations.

International negotiations always start with low ambit claims, the key is to not let them end there.