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Those of us pursing our lips in horror at the homophobia of these ads and who are, anyway, confident that a majority of decent Queenslanders do not vehemently oppose gay marriage miss the point. This type of advertising is not focused on winning 50 per cent of the voters. It is focused at a small part of the electorate - at most perhaps 10 per cent - for whom this issue really matters. For many of that 10 per cent, such an issue is important enough to change a vote. Moreover one's position on gay marriage is often a convenient piece of shorthand for describing the host of presumed opinions held by the candidate. It perhaps summarised as being ''a trendy'' - Americans might say a liberal. (Some will suggest that it's also a dog-whistle appeal to racists, to those who hate boat people, and perhaps to those who hate vegetarians, but there's no real evidence for that.)

The appeal of this sort of attack ad, for those who go down this path, is not in the sudden conversion of a candidate who suddenly thinks that he, or she, might be on the wrong side of some imaginary line representing the opinion of 51 per cent of voters. It is in the way that it invites prevarication, obfuscation, panic and havering by the candidate. In the process it seems to confirm, first, that there is something odd about his or her real position, and, second, that the issue in question is an important one.

Queensland already has same-sex union laws, adopted under a Labor government (without a particularly loud noise from the Katter forces). Campbell Newman is a trendy, to the left of his party on gay marriage. But whatever his views - he is not yet even a member of the LN Parliamentary Party - it seems clear that the LNP does not plan to extend gay marriage, and that it will probably not repeal the existing law. (Repeal could, in any event, be legally difficult, and a serious constitutional question.)

For most voters, thus, gay marriage is a complete non-issue, hardly the most relevant thing to making a voting choice. Even many who disapprove of gay marriage, or who disagree with Newman's view on that subject, are unlikely to judge him on this ground.

For some, however, the idea of gay marriage is an affront to morality and common sense. A politician progressive on such matters is the sort of politician who is progressive on others such as abortion, promiscuity of modern youth, mini-skirts, tolerance of drugs and everything else taking us all to hell in a handbasket. Now we know Newman is one of those dreaded trendies. You can guess without asking that he'll be be useless in the next campaign to restore the death penalty.

Contentious advertising helps make people take note of a new party during an election of the sort in which third parties tend to be squeezed. The LNP is odds-on favourite to win, after a long Labour period in which it has become tired and complacent. But it has hardly ever found its stride because of Labor character attacks on Newman, and, now, this assault from his right. Queenslanders seem to have decided to chuck Labor out without ever getting enthusiastic about the alternative.

But if this could be profitable politics in Queensland - where one-member seats prevail - consider its possible impact in an ACT election later this year, in multi-member seats. Or in a Senate election. In a five-member division in Canberra, a candidate needs 16.7 per cent to win a seat; in a seven-member division, and in the Senate, 12.5 per cent. A candidate who can get half of that will certainly have a very good chance of winning.

Labor and Liberals, and even, if to a lesser extent, the Greens, must appeal to the general electorate, trying, at the least to win 50 per cent of the vote. Realistically, the Greens might be content with 20 per cent, but these days the Greens deny they are a one-issue party and insist they are seeking to govern in their own right.

The individual candidate is not seeking 50 per cent. She is seeking 12 or 17 per cent, and does not care if a large majority of voters flatly disagree with her pitch or her cause. Indeed the more they say they are, the more free publicity she gets. It is far better to be a polarising and controversial candidate than one who is simply unnoticed. Even a party candidate who focuses her campaign on her colleagues, rather than the ''other side'' maximises her share of the party vote.

I have no idea what proportion of the ACT population is vehemently opposed to gay marriage. Or to euthanasia. Or adoption of babies by single persons, or transsexuals. Or abortion. The number is smaller than the number of people actually opposed, because some people will hold such an opinion but, given they recognise themselves to be in a minority position, will not vote on such issues alone.

For some people, however, the issue is not a matter of simple democracy, where majorities should prevail, or of difference of opinion, on matters about which people of good will can disagree; it is, rather a fundamental moral question, the answer to which goes to the very moral legitimacy of the state.

This is, to a degree, the point to which some of the more extreme Christian Right Republicans have come in the US. The US Supreme Court's decision in Roe v Wade - legitimising abortion - virtually deprived the federal government (or at least those who went along with it) of any moral legitimacy. Abortion of any sort, the syllogism goes, is a grave moral sin, akin to murder.

The state can no more authorise the murder of unborn babies than it could authorise the killing of Jews, or of red-headed people. In this sense, many such people think, a candidate's views on abortion - on some such question - is fundamental to his or her fitness for office. Since, moreover, a candidate agitated about abortion is likely to have other non-trendy views on other ''moral'' issues, or on issues such as big government or the right to possess guns, it is perfectly legitimate to use such other issues in efforts to flush out the liberals, the trendies, and the backsliders. The operating principle is that a person is not sound on a litmus issue, for example gun control, is bound to be unsound on deficit budgeting.

Even some very local contests have become vicious brawls. Sarah Palin, for example, made her first venture into politics - to be mayor of an unimportant town - as a crusade on abortion and gun rights, matters completely unconnected with the powers and functions of local government. But right-thinking people knew instinctively where she would stand on other matters. Her opponents - attacked as liberals and wishy-washy - could hardly get to grips with her on the issues that, they argued, actually mattered.

All the more effectively can this be done in ballots where voting is not compulsory, and where, generally, fewer than half of those eligible vote. Primary elections tend to focus on party activists, not the population at large; a good many activists are, as has been remarked, in search for the most extreme candidate with a chance of winning the ultimate contest. This is tested by lacerating attack ads, ones particularly focused on character, and moral positions. Almost inevitably, the effect of such campaigns, among the Republicans at least is to shift even moderates towards the right. In the process, Americans become even more polarised about competing visions of the role of the state, but also about religion and the state.

I doubt that it will ever come to this in Australia, but it will not be for want to trying by a few players who have recognised some of the virtues, as it were, of polarising advertising, confrontational politics, and the urgent need, as they see it, to get immoral and godless socialists away from the crucial levers of government. Since this is such a noble mission or end, it can seem to justify somewhat dubious means. I doubt that Katter himself actually believes such stuff, but he has ever loved being the one they are all talking about.

Jack Waterford is The Canberra Times' Editor-at-Large.

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