For his part Tony Abbott said the Liberals' man for the marginal seat of Dawson, George Christensen, was a still a ''good bloke'' after some of the candidates's old anti-gay, anti-women, anti-Semitic ''jests'' from university days got a fresh airing. It was only last week that a George H.W. Bush-appointed federal judge in California, Vaughn Walker, rejected the ban on same-sex marriage that had become law as a result of a citizens' vote during the 2008 state elections. It is widely known as Proposition 8, or the Marriage Protection Act, which provides that ''only marriage between a man and a woman is valid or recognised in California''. Australia has its own version of the Marriage Protection Act. It was introduced in Parliament in 2004 by the then attorney-general, Philip Ruddock, and said: ''Marriage means the union of a man and a woman to the exclusion of all others, voluntarily entered into for life.'' It added that same-sex marriages ''solemnised'' in a foreign country must not be recognised in Australia. Parliament went along with Ruddock's amendment and passed it.

Just why is a bit of a mystery because, unlike in the US, it is simply not a raging issue in this country, apart from among evangelical groups and established churches. Churches that have been riddled with sexual oppression, and scandalous cover-up of sexual abuse, with a straight face still deliver homilies on homosexuality. A Galaxy poll commissioned by GetUp! in 2007 found that 57 per cent of respondents supported same-sex marriage - up 20 points from when Newspoll tested the issue in 2004. Judge Walker found that the Californian law breached the constitution on a number of grounds. But what made his judgment compelling reading were the pages and pages of ''factual'' conclusions at which he arrived after listening to and weighing a mountain of evidence. For instance: same-sex love and intimacy are well documented in human history; sexual orientation is fundamental to a person's character and individuals do not generally choose their sexual orientation; same-sex couples are identical to opposite-sex couples in the characteristics relevant to form successful marital unions; permitting same-sex marriage will not affect the number of opposite-sex couples who marry, divorce, have children, etc; and same-sex parents are of equal quality as opposite sex parents.

There followed 25 pages of legal reasons, which revolved around violation of the guarantees of equal protection and due process. He said the moral views of supporters of Proposition 8 ''are an insufficient basis upon which to enact a legislative classification''. The legislation had the effect of enshrining opposite-sex couples as superior to same-sex couples. One law professor was quoted as saying the judge had paid homage to the ancient principle: ''Give us the evidence. Prove it.'' Since then Judge Walker has been caught up in a murky campaign to discredit his findings on the basis that he is gay, the implication being that only a straight, married judge would be unbiased when making a decision about same-sex marriage. Anyway, his orders have been stayed pending appeal, and the whole thing is likely to wind up before the US Supreme Court, where the swing judge is Anthony Kennedy.

He wrote the lead judgment in another famous American case, Lawrence v Texas, which said that laws prohibiting sodomy were unconstitutional. How this plays in Australia is a little difficult to predict. If someone were to ask the High Court to rule on the constitutionality of the Marriage Act, it is likely to say that it is a matter for Parliament. After all, we are a country without any great entrenched governing principles of equality or rights. A bold court might read down the phrase ''a man and a woman'' to ''person'', but it's hard to see that happening in a hurry. One of the arguments by proponents of Proposition 8 was that marriage was for the purposes of procreation.

Interestingly, Justice Dyson Heydon from our own High Court attempted to draw some parallels in a similar territory. He wrote that ''criminal law bears the same relationship to the instinct for revenge as does marriage to the sexual appetite''. Glacial is the speed of great change. Little more than a generation ago in the United States and Australia the law did not protect black people and three generations ago women did not have the vote. Loading Today that discrimination, unfairness and inequality are unthinkable - just as the denial of gays' right to marriage will be a total puzzle to those less than a generation away from today. justinian@lawpress.com.au