David Blankenhorn, president of the Institute for American Values, takes on the issue of same-sex marriage in The Future of Marriage, soon to be released by Encounter Books. Blankenhorn brings a wealth of insight to the book, arguing that Western nations have been “deinstitutionalizing” marriage for decades.

In “Defining Marriage Down . . . is No Way to Save It,” published in this week’s edition of The Weekly Standard, Blankenhorn summarizes his argument. In a nutshell — marriage has been seriously weakened and is now threatened as our central social institution. Marriage has been “deinstitutionalized” through legal, cultural, ideological, and lifestyle revolutions. Proposals about same-sex marriage can come only after marriage has been seriously weakened as an institution. But, even though proponents of same-sex marriage claim to value marriage as an institution, the real impact of same-sex marriage would be the further deinstitutionalization of marriage itself.

In Blankenhorn’s words:

Does permitting same-sex marriage weaken marriage as a social institution? Or does extending to gay and lesbian couples the right to marry have little or no effect on marriage overall? Scholars and commentators have expended much effort trying in vain to wring proof of causation from the data–all the while ignoring the meaning of some simple correlations that the numbers do indubitably show.

Much of the disagreement among scholars centers on how to interpret trends in the Netherlands and Scandinavia. Stanley Kurtz has argued, in this magazine and elsewhere, that the adoption of gay marriage or same-sex civil unions in those countries has significantly weakened customary marriage, already eroded by easy divorce and stigma-free cohabitation.

More, based on recent research:

The correlations are strong. Support for marriage is by far the weakest in countries with same-sex marriage. The countries with marriage-like civil unions show significantly more support for marriage. The two countries with only regional recognition of gay marriage (Australia and the United States) do better still on these support-for-marriage measurements, and those without either gay marriage or marriage-like civil unions do best of all.

In some instances, the differences are quite large. For example, people in nations with gay marriage are less than half as likely as people in nations without gay unions to say that married people are happier. Perhaps most important, they are significantly less likely to say that people who want children ought to get married (38 percent vs. 60 percent). They are also significantly more likely to say that cohabiting without intending to marry is all right (83 percent vs. 50 percent), and are somewhat more likely to say that divorce is usually the best solution to marital problems. Respondents in the countries with gay marriage are significantly more likely than those in Australia and the United States to say that divorce is usually the best solution.

Finally:

Similarly, it’s time to recognize that the beliefs about marriage that correlate with the push for gay marriage do not exist in splendid isolation, unrelated to marriage’s overall institutional prospects. Nor do those values have anything to do with strengthening the institution, notwithstanding the much-publicized but undocumented claims to the contrary from those making the “conservative case” for gay marriage.

Instead, the deep logic of same-sex marriage is clearly consistent with what scholars call deinstitutionalization–the overturning or weakening of all of the customary forms of marriage, and the dramatic shrinking of marriage’s public meaning and institutional authority. Does deinstitutionalization necessarily require gay marriage? Apparently not. For decades heterosexuals have been doing a fine job on that front all by themselves. But gay marriage clearly presupposes and reinforces deinstitutionalization.

Blankenhorn’s analysis is important for multiple reasons. First, his focus on the deinstitutionalization of marriage allows a more dispassionate analysis of the whole marriage question. Second, his acknowledgment that these deinstitutionalizing trends predated calls for same-sex marriage adds much-needed background information. It is important that defenders of marriage acknowledge that marriage was in big trouble long before homosexuals demanded same-sex inclusion. Third, his shift of emphasis in research from causation to correlation gets to the heart of the issue — what convictions and habits are necessary to the protection and recovery of marriage. Fourth, his argument that same-sex marriage would further deinstitutionalize marriage is a natural conclusion drawn from the research on the state of marriage where same-sex marriage is accepted and legalized.

Same-sex marriage is a moral issue. Marriage itself is a moral issue. Nevertheless, there are effects of the deinstitutionalization of marriage that go far beyond abstract moral debates. Real lives are at stake, and those lives — especially those of children — are put at great risk when marriage is defined downward.