The US Supreme Court announced last week that it will review the constitutionality of same-sex marriage. Last November the Sixth Circuit Court of Appeals ruled in favour of bans in Ohio, Kentucky, Tennessee and Michigan. This decision is now being appealed.
There is great rejoicing amongst supporters of same-sex marriage. “The justices have the power and the responsibility to give meaning to the promises embedded in the Constitution, and end the exclusion and inequality of gays and lesbians in America,” the New York Times declared in its editorial. At the moment 36 states and the District of Columbia have effectively legalised it, although in nearly all cases it was imposed by courts rather than voted upon democratically in the state legislatures.
The Times’s editorial argues that Lawrence v. Texas in 2003 and US v Windsor in 2013 are compelling precedents. In the former, the Court ruled that the Constitution protects “adult persons in deciding how to conduct their private lives in matters pertaining to sex.” In the latter, it struck down the definition of marriage as between a man and a woman in the federal Defense of Marriage Act (DOMA). With that the sluicegates opened. Court after court has found that it is discriminatory for a state to restrict marriage to one man and one woman.
So, on the constitutional front, it must be admitted, things do not look good for opponents of same-sex marriage. There is the usual yadda-yadda by the commentariate about the conservative faction and the liberal faction and the swing voter, Justice Anthony Kennedy.
But to some extent this pessimism is supported by social trends. According to last year’s Gallup poll, 55 percent of American support the legalisation of same-sex marriage. Amongst 18 to 29-year-olds, nearly 80 percent are in favour. This means that support will probably grow year by year.
Since same-sex marriage has ceased to be a democratic issue to be resolved in legislatures, perhaps opinion polls don’t really matter too much any more, but in the lead-up to April, when the Supreme Court will hear oral arguments, the fine grain of the polling data could change the mind of some justices.
Which minority groups deserve the most protection? It is a sobering thought for supporters of natural marriage, but married couples will soon be a minority group in the United States. Last year one economist crunched Department of Labor statistics and claimed that single Americans constituted more than half of the adult population for the first time since this figure was first gathered in 1976. This trend is bound to gather speed. Of course, the number of people in natural marriages is much greater than the number of homosexuals and certainly than the number of homosexuals who wish to be married. But nonetheless it is or soon will be a minority. If that is the case, doesn’t the claim that legalisation will harm conventional marriages deserve extra consideration? A minority group will be injured. More importantly, does society benefit if the group which educates future generations is shrinking? 
The poll data have been sub-divided and analysed and parsed in any number of ways, but significant questions still remain unanswered. We know the sectors supporting same-sex marriage by age, by sex, by race, by political affiliation, by education, by region, and by religion. But curiously, there seems to be almost no data on support by marital status. What percentage of married couples with children support same-sex marriage? With young children? They have the most to lose. Why don’t we know what they are thinking?
Supporters of same-sex marriage are keen to depict the movement as a snowball picking up support from all sectors of society. But no one seems to be interested in understanding the opposition. It’s quite probable that most of it comes from the people who have invested the most in marriage. For many of them, opening the marriage doors to gay and lesbian couples could seriously reduce the value of that investment. But we don’t know. The pollsters have focused on measuring biases like religion and political persuasion, rather than on perceptions of harm.
More fine-grained data would also be welcome about the state of marriage in American society. According to another Gallup poll, between 2001 and 2013, the moral acceptability of gay and lesbian relations rose by 19 percent, from 40 percent of people surveyed to 59 percent. At the same time, the moral acceptability of having a baby outside of marriage rose by 15 percent, of sex between an unmarried man and woman by 10 percent, and of divorce by 9 percent. Support for polygamy doubled, from 7 to 14 percent. Why won't these figures drift up when gay marriage is legalised?  
Twenty-somethings are overwhelmingly in favour of legalising same-sex marriage. But do they know what marriage is? A 2013 Gallup poll of 18 to 34-year-olds found that only 35 percent were married or had been married; 9 percent were not married and intended to remain single forever. Overwhelming support for a product which 65 percent have not used and 9 percent swear they will never use is not an informed endorsement. 
Gays and lesbians also need to pore over the data. Most of them are clamouring for legalisation to obtain the social recognition and acceptance that traditionally came with marriage. But at the same time as they are crashing the marriage club, the club is struggling with a serious public relations problem and is bleeding membership. The authors of the Gallup report summed the situation up as follows:

“Americans' views of the importance of being married when two people want to spend their lives together or have a child has declined in recent years. Thus, while most younger Americans who have never married express an attitudinal interest in eventually doing so, fewer hold the underlying attitude that such an action is important.”

If this is the case, shouldn’t gays and lesbians take Groucho Marx’s advice: “I don’t care to belong to any club that will have me as a member”?
With all its problems, traditional marriage had enormous vitality and resilience. But after two generations of widespread divorce, contraception, and co-habitation, it is limping badly. We need to know more, much more, about the effect of admitting homosexual couples to the club. Michael Cook is editor of MercatorNet.