In a month, most of us will make our way to polling booths to indulge in a strange ritual known as preferential voting. The system is not unique to Australia; some form of the preference system is also used in constituencies as diverse as Latvia, Nepal, Malta and Nauru. But the vast majority of democracies still rely on the more direct method of election known as first past the post: you vote for one candidate and whoever gets the most, wins. Simple and, one would think, fair.
Australians found it fair for the first few years after Federation. When the early stew of vested interests settled down into a direct contest between Labor and non-Labor, first past the post made perfect sense. But the rise of the Country Party complicated matters. Many elections became three-cornered contests between Labor, the city-based Liberals (later the Nationalists) and their conservative country cousins. The anti-Labor vote was split, and Labor candidates were often elected with less than 50 per cent of the vote.
Things came to a head in 1918 in a byelection in the Western Australian seat of Swan, when the Labor candidate won with just 34 per cent, the Country Party candidate managed 30 and the Nationalist 29.
Conservatives were outraged, and since they were in control of Federal Parliament, were in a position to do something about it. Two months later, another byelection was due in Corangamite, Victoria, and this one was conducted under the preferential system. The Labor candidate was well ahead on primary votes, with 42.5 per cent. But after a tight exchange of preferences, the Victorian Farmers Union nominee finished on 56.3 per cent after distribution.
Preferential voting gave everyone two bites of the cherry, but it was the conservatives, with their two large popularly based parties, who benefited. The urban and rural parties promptly formed a coalition in government, and have only occasionally been parted since.
The system also made it possible for other minor parties to rise. So far, only the Country Party (now the Nationals) has succeeded in gaining seats in the House of Representatives, although that may change this year.
But the preferences of the minor parties have determined the outcome of many seats, and more than a few governments. The system designed to keep Labor out of office actually saved Bob Hawke's government in 1990, when Greens preferences delivered the vital seats. Greens voters had grown somewhat disenchanted with Labor, but they feared the alternative more.
And this is the nub of the preferential system: where first-past-the-post elected the candidate most loved, preferential delivers the candidate least loathed.
You may not like any of those on offer much, but voting - or at least enrolling and turning up at the polling booth - is compulsory. While there may not really be a candidate voters want to put first, there is almost always someone they want to put last. The great advantage of preferential voting is the opportunity it gives for the venting of spleen.
This makes it a particularly appropriate for the current election. By the middle of June, we had the extraordinary situation in which no one wanted either Kevin Rudd or Tony Abbott; according to the more reliable polls, both the then prime minister and the Leader of the Opposition were in negative territory. If compelled to choose, they would take Rudd, but many would hold their noses while doing so. He was seen as a crashing disappointment; they had given him their hope and trust, and received (as they saw it) little in return. Abbott was still seen as a bit of a joke; he had many appealing qualities, but they were not those needed or wanted in a head of government.
A plague upon both their houses, Hobson's choice, the lesser of two evils. Better the devil you know. These cliches seemed to inform the public mood. In 1996, commentator Malcolm Macgregor summed up the result thus: "John Howard only won because he was standing against Paul Keating. If he had been standing unopposed he would have lost." Rudd's rapidly dwindling band of supporters could relate to that.
Despite the brandishing of some dodgy polling by his enemies, Labor probably would have won under Rudd. But even Rudd's most adoring fans (his pets Jasper and Abby) would find it hard to claim it was a popular victory.
Rudd's fall inside the Labor Party had been even more dramatic than the collapse in the polls. A political vacuum had formed in both areas and Julia Gillard was ready, and finally willing, to fill it.
But the clouds did not lift in quite the way the Labor heavies had expected. The polls showed Labor's vote settling back to where it was under Rudd; still a respectable lead, but not what had been planned. There will be no landslide for Gillard. The hard fact remains that if she wins (and she probably will), it will be because a lot of people are putting Abbott last.
Others will turn inward and vote locally: they will suppress the fact that whoever they vote for, either Gillard or Abbott is going to be prime minister. Some will register a protest vote with a minor party or an independent, but if their vote is to be valid they will have to fill in all the squares, so they will still have to choose: who do you put last?
The pessimists were right: this election really is a race to the bottom, although not - at least not only - in the sense they feared. The winner will be the one who isn't the loser.
Mungo MacCallum is a political commentator.