Preferential voting allows society to compromise and choose someone who is the least hated. There are other systems of voting − imagine if each of us could only choose one party from the list. Then we run the risk of choosing someone unpopular, and missing out on having our say about the final two candidates.

That's the way it is in the US, and they get locked into having two parties whose supporters inevitably grow to hate each other.

It's good to have more parties: it allows more ideas to be be pitched 💡💫

In preferential voting, we get to have lots of parties − if you happen to vote for a party who ends up coming last, it doesn't matter; your vote gets reassigned to whoever you wrote as number 2. Then the next party gets eliminated, and the votes get reassigned again, as we see in the Sankey diagram above.

At each step, the votes still add up to 100 − anyone who voted yellow doesn't suddenly have their vote go missing.

Notice that if you want a say in the final showdown (the last two parties), then whether you put them as your first two preferences or your last two, it still has the same effect. 📊

So even if you want Liberal or Labor to win, if you actually put them first, you're missing out on fully having your say. Even the most rusted-on Liberal and Labor supporters would admit that they might like to change a policy here and there; maybe add something that's missing. The parties themselves change their policies every few years, so would it be a sin to be one step ahead of them, asking for a change?

By voting for a minor party first and a major party later, you're able to convey "sure, this is the major party I prefer. But I wish they'd legalise cannabis. I wish they'd give some more justice to animals. I wish they'd put more effort into ensuring Australia is a place for big ideas and not just a place to dig things out of the ground." 🔬

As more people switch to newer parties, everyone else sees the increase in votes, and they become more likely to vote for these parties themselves, in a virtuous cycle. It has to start somewhere; and if you choose to be ahead of the pack, you'll be making your future self proud. 🔮