Ronald Bailey of Reason has reviewed a number of studies on the impact of same-sex civil marriage for the Wall Street Journal. He observes that in the Netherlands, the state created a new category of legally-recognized unions open to all couples, including same-sex couples, in 1998 before allowing same-sex civil marriages in 2001. And in the years since, these new non-marital unions, known as registered partnerships, have grown in popularity:
A 2009 study by University of Sherbrooke economist Mircea Trandafir investigated the effect of the legalization of same-sex marriage in the Netherlands, the first country to recognize same-sex marriage. In 1998, the Dutch created registered partnerships, which are open to all couples, and in 2001 a law allowing full same-sex marriages. His analysis found that same-sex marriage leads to a decline in the different-sex marriage rate, but not in the different-sex union (marriage plus registered partnership) rate. In other words, Dutch heterosexual couples are taking advantage of the “marriage lite” registered partnership alternative.
At the time of Prof. Trandafir’s study, the chief difference between registered partnerships and marriage was that the former could be dissolved at the civil registry by mutual agreement. In a 2012 West Virginia Law Review article, Mercer School of Law professor Scott Titshaw shows that the political compromises provoked by the initial refusals to extend full marriage rights to same-sex couples result in a proliferation of civil union alternatives. Prof. Titshaw agrees with Prof. Trandafir that different-sex couples increasingly find the new marriage alternatives attractive; in effect, refusing to give full legal recognition to same-sex couples ends up diminishing the status and benefits associated with conventional marriage for everyone. Ironically, conservatives, by opposing the extension of full marriage rights to gay people, have ended up weakening the institution they sought to defend. [Emphasis added]
Though hardly conclusive, Trandafir and Titshaw’s findings suggest that the alternative to the widespread adoption of same-sex civil marriage is further deinstitutionalization, but also that the establishment of same-sex civil marriage won’t necessarily end the deinstitutionalization process. One wonders what will happen to civil unions in states that permit same-sex civil marriage. Institutional inertia suggests that these non-marital or quasi-marital institutions will survive, and that they will find a constituency among different-sex couples seeking alternatives to traditional marriage.