Since secular marriage has long encompassed unions that depart sharply from sacramental marriage, the optimistic traditionalist sees that adding same-sex unions doesn’t constitute a loss. And he sees that it is a gain for traditionalists when compared to a world where gays gained visibility and acceptance but never sought marriage rights. What if instead they’d demanded mere tax benefits, hospital visitation, and other material concessions like what has been called “civil unions”? Had that happened, civil unions would’ve quickly spread from gays to non-traditionalist straights. With the spread of civil unions, all continuity with the past would’ve been lost. A full break with traditional marriage would’ve been upon us.

Instead, a culturally influential minority is now included in marriage, so it remains the default way that couples join; religious people are as free as ever to marry in a fully traditional sense; and secular straights retain more traditional aspects and attitudes than they would if they’d switched over to a new paradigm of coupledom.

That story is more plausible to me than the one where traditional marriage survived–despite centuries of changes driven by the Enlightenment–until gays came along and struck the decisive blow against the old order by successfully joining it. If traditionalists stay focused on denying civil marriage to gays, they’ll waste their time on a battle they can’t win. If they persuade themselves that same-sex nuptials have struck the decisive blow against marriage, they’ll stop trying to influence the institution entirely. But if traditionalists pick their battles, it is conceivable to me that a decade or two hence, even as same-sex marriage is legal everywhere in the United States, there could also be a significant increase in the number of religious people who embrace the orthodox parts of their respective marriage traditions and a significant decrease in the society-wide divorce rate.