The success of the campaign to legalise gay-marriage across many western countries is quite momentous. It is astonishing to see how fast political and popular opposition to gay marriage (or, as supporters call it, 'marriage') is crumbling in the face of the reasonable demand for public justification for banning it. The feeble excuses for arguments trotted out by bishops, pundits, activists, politicians and lawyers arguing before the US supreme court are increasingly perceived for what they are: the rationalisations of bigoted prejudices.
And yet, there is something disappointing in how the gay-marriage debate is being won. Proponents have overwhelmingly argued against discrimination, rather than for the freedom to be different. They have argued that it is unfair to treat their relationships differently from heterosexual ones because they are in every significant respect the same. Doing so violates the principle of equality under the law: treating similar cases in the same way. There are hundreds if not thousands of government benefits and ancillary rights linked to marriage status which it is unfair to deny to people on the basis of an irrelevant feature: their sexuality.