Elvert Barnes | Creative CommonsThe US Supreme Court’s opinion in Obergefell v Hodges – it may come out today, or next week – will be historic whatever it decides. The main question is whether the Fourteenth Amendment to the US Constitution with its guarantee of the “equal protection of the laws” requires states to allow same-sex marriage.

Either it will be a turning point as famous as Loving v Virginia in the 1960s, defining this human rights issue of our time well beyond the US; or it’ll rule that same-sex marriage is a matter for states to permit or not, not something nine judges sitting in Washington should impose.

As someone who’s happier living under the British constitution (where this sort of issue is decided by Parliament) I’ve some sympathy with what’s seen in America as the “conservative” position, even though I strongly support same-sex marriage. In Britain, same-sex marriage is now permanent and broadly accepted – in large part because Parliament brought it in, rather than a court ruling. I wonder whether a great court victory this June really will be best for lesbian and gay rights in America, in the medium and longer term.

But that’s a political and social view. Courts must answer the legal questions they’re asked, so the Justices can’t merely say who should decide on gay marriage. They have to squarely tell us whether or not its refusal is compatible with the “equal protection of the laws”. If I were among them, I suspect I’d be with Justices Ginsburg, Breyer, Sotomayor and Kagan in saying it’s not. Perhaps the social controversy simply has to be resolved by judges in America’s legal culture, just as Britain’s way of doing it reflects our culture – and as Ireland’s choice of a referendum reflected its distinct constitutional culture, too.

What do I guess will happen? American commentators are focusing on Justice Kennedy, who’s likely to swing the opinion one way or the other. Will he follow the pro-gay marriage logic Justice Scalia saw in his opinion in US v Windsor two years ago? Or the federalist logic Chief Justice Roberts saw in it? My guess is that Scalia’s fears will be realised, and that we’ll be treated to one of Scalia’s most famous and trenchant dissents. But a guess is all it is.

What’s interesting from this side of the Atlantic is how European law would deal with this issue – which brings me to the second legal question in the case, because there’s more than one. They are not only

Does the Fourteenth Amendment require a state to license a marriage between two people of the same sex?

but, if not,

Does the Fourteenth Amendment require a state to recognize a marriage between two people of the same sex when their marriage was lawfully licensed and performed out-of-state?

If the court says “No” to the first question, it will have to answer the second. Must states who forbid it nonetheless recognise same-sex marriage where it’s entered into in other states?

Many American lawyers seem to doubt this question is really capable of a different answer from the first, and there was a feeling during oral argument (which you can hear below thanks to the Oyez Project at IIT Chicago-Kent College of Law) that it had little life of its own. Justice Ginsburg, I noticed, seemed to accept that the “full faith and credit” provision of the Constitution would not require states to accept each other’s laws in the way contended for.

But in Europe the questions may truly be legally distinct. The question whether European democracies must all permit same-sex marriage was decided not long ago by the European Court of Human Rights in Schalk & Kopf v Austria: they don’t have to. The court said (para. 61) that it

would no longer consider that the right to marry enshrined in Article 12 must in all circumstances be limited to marriage between two persons of the opposite sex …

but that (paras. 61-2)

as matters stand, the question whether or not to allow same-sex marriage is left to regulation by the national law of the Contracting State …

The Court reiterates that it must not rush to substitute its own judgment in place of that of the national authorities, who are best placed to assess and respond to the needs of society …

This is basically the sort of “federalist” approach that might prevail in Obergefell. If the US Supreme Court leaves same-sex marriage as a matter for states to decide, it’ll essentially be giving them the kind of “margin of appreciation” Strasbourg has allowed European states.

But the second question, about recognition of same-sex marriage lawfully entered into elsewhere, is here a question of EU free movement law, not primarily one of human rights. Article 2 of Directive 2000/38 provides that an EU citizen exercising feee movement rights may be accompanied by his or her spouse, a term which is undefined. And just as in America, some EU states have enthusiastically adopted same-sex marriage while others set their faces against it.

Given the free-movement purpose of the Directive, and given that article 9 of the EU Charter of Fundamental Rights does not (unlike article 12 ECHR) specifically refer to “men and women”, I feel confident the European Court of Justice would rule in favour of what you might call “gay marriage exportability” between EU states. A case must arise one day; and given the proximity of the Netherlands, France, Belgium and Denmark to Germany (which as yet denies same-sex marriage) that case may even, like Schalk & Kopf and Obergefell, have a German name.

Perhaps it’s the multinational nature of Europe that makes the recognition question more separable from the fundamental principle of same-sex marriage than it may be in America; perhaps it’s the institutional division of the two questions between two different courts. If the cases go as I suspect, those will be interesting questions for academics. But I’m getting well ahead of things. We’ll soon know what the Justices say in Obergefell, and which way legal history’s going.