A three judge panel of the US Seventh Circuit Court of Appeals has unanimously struck down same-sex marriage bans in Wisconsin and Indiana. You can read the history of the case here and the opinion here.

This verdict is, nowadays, not remarkable. But what is surprising is the surprisingly strong sarcastic language used by judge Richard Posner in his opinion in dismissing the state governments’ arguments for retaining the ban. He was particularly harsh on the ‘for the sake of the children’ argument.

The challenged laws discriminate against a minority defined by an immutable characteristic, and the only rationale that the states put forth with any conviction— that same-sex couples and their children don’t need marriage because same-sex couples can’t produce children, intended or unintended—is so full of holes that it cannot be taken seriously. (p.7)
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At oral argument the state’s lawyer was asked whether “Indiana’s law is about successfully raising children,” and since “you agree same-sex couples can successfully raise children, why shouldn’t the ban be lifted as to them?” The lawyer answered that “the assumption is that with opposite- sex couples there is very little thought given during the sexual act, sometimes, to whether babies may be a consequence.” In other words, Indiana’s government thinks that straight couples tend to be sexually irresponsible, producing unwanted children by the carload, and so must be pressured (in the form of governmental encouragement of marriage through a combination of sticks and carrots) to marry, but that gay couples, unable as they are to produce children wanted or unwanted, are model parents—model citizens really—so have no need for marriage. Heterosexuals get drunk and pregnant, producing unwanted children; their reward is to be allowed to marry. Homosexual couples do not produce unwanted children; their reward is to be denied the right to marry. Go figure. (p.19)
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To return to where we started in this opinion, more than unsupported conjecture that same-sex marriage will harm heterosexual marriage or children or any other valid and important interest of a state is necessary to justify discrimination on the basis of sexual orientation. As we have been at pains to explain, the grounds advanced by Indiana and Wisconsin for their discriminatory policies are not only conjectural; they are totally implausible. (p.38)
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The states’ concern with the problem of unwanted children is valid and important, but their solution is not “tailored” to the problem, because by denying marital rights to same-sex couples it reduces the incentive of such couples to adopt unwanted children and impairs the welfare of those children who are adopted by such couples. The states’ solution is thus, in the familiar terminology of constitutional discrimination law, “overinclusive.” It is also underinclusive, in allowing infertile heterosexual couples to marry, but not same-sex couples. (p.39)

The opinion also emphasized the important fact that just because a rule or law is arbitrary does not mean that it need not be fair.

A degree of arbitrariness is inherent in government regulation, but when there is no justification for government’s treating a traditionally discriminated-against group significantly worse than the dominant group in the society, doing so denies equal protection of the laws. One wouldn’t know, reading Wisconsin’s brief, that there is or ever has been discrimination against homosexuals anywhere in the United States. The state either is oblivious to, or thinks irrelevant, that until quite recently homosexuality was anathematized by the vast majority of heterosexuals (which means, the vast majority of the American people), including by most Americans who were otherwise quite liberal. (p.24)

It is like speed limits on roads. Any given limit is an arbitrary figure. But that does not mean there should be no limits. But it does mean that the limit should be applied fairly to all. ‘Equal protection of the laws’ is a fundamental legal principle.