Steve Schmidt, the operations chief of the 2008 McCain presidential campaign, gave a talk to the Log Cabin Republicans, recommending that the Republicans should support gay marriage. The talk was problematic, since neither the moral rationale given for supporting gay marriage, nor the possible political consequences were given more than a muddy, and partial focus.

In his speech, Schmidt said:

[Marriage] has always been defined as the legal union of a man and a woman

Pretty much always and everywhere, throughout history, it has been assumed, without puzzlement or contention, or precise definition, that marriage is the union of a man and a woman, whether in a legal framework or in the complete absence of one.

But Schmidt’s definition misses out a central feature of marriage — the feature that distinguishes marriage from a mere partnership of adults. Marriage is the union of a man and a woman for the purpose of producing and raising children. If the goal of children is missed out, the the purpose of marriage is lost. Without the goal of children, the adult partnership may be something of value, but it is not nearly the same value as a partnership that produces children. Life, liberty and the pursuit of happiness originates in each and every child and grows with each. To set in place a system of laws that allows this to occur, and nurtures it every step of the way is thus quite surely part of the national creed. And for that reason, the definition of marriage is central to any national creed.

Having missed out children, Schmidt’s thinking on marriage very rapidly goes astray.

it is a tradition, not a creed, or, at least, not a national creed. It is not how we define ourselves as Americans.

In the American context, it is not defined in a national creed because people took it as something whose purpose was obvious, unchallenged, and not something in desperate need of clarification. And that same context applies over worldwide history.

we should understand that traditions do change over time in every society

Well, yes. Sometimes for better, and sometimes for worse. So which is it? And decided on what grounds?

I respect the opinions of Americans who oppose marriage for gay couples on religious grounds.  I may disagree, but if you sincerely believe God’s revealed truth objects to it then it is perfectly honorable to oppose it.  But those are not the grounds on which a political party should take or argue a position.  If you put public policy issues to a religious test you risk becoming a religious party, and in a free country, a political party cannot remain viable in the long term if it is seen as sectarian.

That is rather akin to a method of thinking that is more commonly seen among Catholic Democrats who wish to vote for legalized abortion — “I personally think it is wrong, but I am not going to impose my religious beliefs on others”. But what’s believed on religious grounds may simultaneously be believed on rational grounds. For example, a firm belief that theft is wrong on religious grounds is not thereby a bar to voting for secular laws against theft — good secular non-religious reasons against theft can be found.

Certainly, what is purely a religious matter should not be imposed on others who disagree. Opposition to abortion is not a purely religious issue, and neither is support for traditional marriage. If political parties have to find support from those whose thinking is partly religious, then they will just have to live with it, for the good secular reasons.

As in fact they always have: the opposition to slavery was such an issue, partly based in religious belief and partly on rational grounds. The various political parties of the 1800s danced around that issue for quite some time. Schmidt’s line of thinking could  have the Republican party end up dancing with two partners who dislike each other, and in each alternate dance they would try to keep the other partner happy. You can keep that up for quite a while, just like the Whigs. But then they will end like the Whigs.