The polarisation of the supreme court was laid bare on Tuesday, the first of two days of hearings on gay marriage. Photograph: Jewel Samad/AFP/Getty Images
US supreme court justices tore into a central argument of opponents of same-sex marriage on Tuesday as the court heard for the first time arguments over whether gay couples have a constitutional right to wed.
The deep polarisation of the court on social issues was laid bare on the first of two days of hearings on gay marriage, which saw liberal justices shoot down claims that same sex-couples should not be allowed to wed because they cannot procreate, while the conservatives attacked rapid change as undermining centuries of tradition.
But none of the parties in the cases under consideration on Tuesday, involving a 2008 California referendum barring gay marriage, may get the definitive rulings they are seeking. One persistent line of questioning raised the prospect that the court will sidestep a decision on the basis that the plaintiffs – the proponents of the gay-marriage ban – do not have legal standing to bring the case after the state of California declined to do so when the referendum result was overturned by a federal court.
Neither Justice Anthony Kennedy, who is regarded as the potential swing vote on this issue, nor the liberal justices appeared eager for the court to make a sweeping ruling.
Kennedy, who said the court may be entering "uncharted waters" by deciding on who has the right to marry, also wondered aloud why the justices had agreed to hear the case. "I wonder if this case was properly granted," he said.
A second case, over a federal law preventing the government from recognising same-sex unions, is to be heard on Wednesday.
A considerable amount of the questioning from the bench on Tuesday focused on whether the central purpose of marriage is procreation. Charles Cooper, legal counsel for four Californians seeking to uphold the results of Proposition 8, barring gay marriage in the state, told the court on Tuesday that the inability of same-sex couples to have children together meant that to allow them to wed would change the historic definition of marriage.
"We are saying the interest in marriage and the state's interest and society's interest in what we have framed as responsible procreation is vital. But at bottom, with respect to those interests, our submission is that same-sex couples and opposite-sex couples are simply not similarly situated," he said.
But that position was met with deep scepticism and even derision from several of the justices. Sonia Sotomayor asked how permitting gay couples to marry interfered with procreation. She then pressed Cooper on whether his argument meant that sterile heterosexual couples should not be permitted to wed because they cannot have children.
Kagan leapt in. "Suppose a state said that because we think that the focus of marriage really should be on procreation, we are not going to give marriage licences anymore to any couple where both people are over the age of 55. Would that be constitutional?" she asked.
Cooper said it would not, but tried to suggest that age didn't matter. "I can assure you, if both the woman and the man are over the age of 55, there are not a lot of children coming out of that marriage," Kagan said, to laughter from the audience.
Justice Ruth Bader Ginsberg picked up on the theme, asking whether someone serving a life sentence in prison should be prevented from marrying because there is no possibility of them becoming a parent.
Cooper struggled for an answer.
Sotomayor also pressed Cooper on whether it would be acceptable to discriminate against gay couples on grounds other than marriage.
"Outside of the marriage context, can you think of any other rational basis for a state using sexual orientation as a factor in denying homosexuals benefits or imposing burdens on them? Is there any other rational decision-making that the government could make? Denying them a job, not granting them benefits of some sort, any other decision?" she asked. Cooper said he could not.
Kagan pressed the lawyer on how allowing gay couples to marry possibly harms the state's interests, as it does not interfere with the right or ability of heterosexuals to procreate. Cooper responded that the real question is whether or not redefining marriage to include same-sex couples would advance the interests of marriage.
The charge against arguments in favour of gay marriage was led by the conservative justice Antonin Scalia. "If you redefine marriage to include same-sex couples, you must permit adoption by same-sex couples, and there's considerable disagreement among sociologists as to what the consequences of raising a child in a single-sex family, whether that is harmful to the child or not. Some states do not permit adoption by same-sex couples for that reason," he said.
Ginsburg noted sharply that California already permits same sex couples to adopt.
Justice Anthony Kennedy said Scalia may have a point, but there was another interest to consider. "There's substance to the point that sociological information is new. We have five years of information to weigh against 2,000 years of history or more. On the other hand, there is an immediate legal injury or what could be a legal injury, and that's the voice of these children.
"There are some 40,000 children in California that live with same-sex parents, and they want their parents to have full recognition and full status. The voice of those children is important in this case, don't you think?"
Theodore Olson, counsel for opponents of the gay-marriage ban, said the referendum "walls off the institution of marriage" to gay people – something he said society does not have the right to do.
"It's an individual right that this court again and again and again has said the right to get married, the right to have the relationship of marriage is a personal right. It's a part of the right of privacy, association, liberty, and the pursuit of happiness," he said.
Scalia challenged Olson to name the date when existing laws on barring gay marriage breached the constitution. "I'm curious. When did it become unconstitutional to exclude homosexual couples from marriage? 1791? 1868, when the 14th amendment was adopted?" he asked.
Olson threw the question back by noting that interracial marriage was illegal in some US states until 1967, and asking when that prohibition became illegal.
Scalia pressed the issue, asking whether the bar on gay marriage has always been unconstitutional. Olson said he could not give a specific date. "So how can I decide?" asked Scalia.
The court also heard from the Obama administration, which sent the US solicitor general, Donald Verrilli, to the hearing. He faced questions over the government's position that California and other states which permit same-sex civil unions must go all the way and allow gay marriage.
Verrilli was asked if that was not unfair, in that it punished those states which have made some steps toward equality by forcing them to introduce a measure they may not want to, while the 30 states that have a total bar on gay marriage would not be obliged to make any change.
The solicitor general responded that the administration would like to see all states permit gay marriage in time.
Justice Alito asked Verrilli if there is not a need to tread carefully with such a sensitive issue.
"You want us to step in and render a decision based on an assessment of the effects of this institution which is newer than cell phones or the internet? I mean, we do not have the ability to see the future. On a question like that, of such fundamental importance, why should it not be left for the people, either acting through initiatives and referendums or through their elected public officials?" he asked.
Verrilli replied that not doing anything also has an impact. "The argument here about caution is an argument that, well, we need to wait. We understand that. We take it seriously. But waiting is not a neutral act. Waiting imposes real costs in the here and now. It denies to the — to the parents who want to marry the ability to marry, and it denies to the children, ironically, the very thing that petitioners focus on is at the heart of the marriage relationship."
For all the passions and expectations raised by the hearings, the court may yet sidestep the issue precisely because it is so divisive. Part of the hearing focused on whether the four private individuals seeking to uphold Proposition 8 ban on gay marriage had the authority to bring the case to the supreme court after the California state government decided not to defend the measure.
Cooper argued that referendums are designed to force politicians to fulfil the will of the people, and that if ordinary individuals cannot then seek legal redress that gives those same politicians an officials an effective veto over the outcome of the vote.
Justice Sotomayor was sceptical. She asked what injury had been created to the four individuals who brought the case to the supreme court. Cooper responded that the injury was to all the people of California.