The President’s Marriage Agenda for the Forgotten Sixty Percent,” despite the impression its title might give, was released Sunday not by the Obama administration but by the Institute for American Values and the National Marriage Project at the University of Virginia. It is a timely, compelling, and important report, but it falls short in a basic way: it never once even attempts to say what marriage is. But you cannot advance a marriage agenda without knowing what marriage is and why it matters for public policy, as my co-authors and I argue in our new book, What Is Marriage?

The leadership of the Institute for American Values, after embracing the redefinition of marriage in a high-profile change of heart earlier this year, hopes this report launches “a new conversation on marriage.” The authors urge political leaders to encourage “community-based and focused public service announcements that convey the truth about marriage, stability and child wellbeing to the next generation of parents.”

Well, what is the truth about marriage?

The report rightly notes that “marriage is not merely a private arrangement; it is also a complex social institution.” But the report never says what this complex institution is, or why it ought to be governed by the standard marital norms of monogamy, sexual exclusivity, and a pledge of permanence—norms that many leading defenders of redefining marriage explicitly reject. Yet without these norms—and the intelligible basis that grounds them—marriage can’t do the work that the authors want it to do.

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That is important work indeed, as the report explains. It helpfully documents the retreat from marriage afflicting today’s middle class and how fixing this “is the social challenge for our times.” While in the 1980s “only 13 percent of the children of moderately educated mothers were born outside of marriage,” today that figure has “risen to a whopping 44 percent.” Indeed, the majority of births to women under thirty “now occur outside of marriage.”

Although some have tried to characterize the disappearance of marriage as a problem facing only lower-class America or the black community, the report notes that “family instability can now be found in Middle America almost as frequently as it is among the least educated sector of the population.” And the disappearance of marriage has social costs, especially increased poverty and decreased social mobility, as “researchers are now finding that the disappearance of marriage in Middle America is tracking with the disappearance of the middle class in the same communities. . . . This decline of marriage in Middle America imperils the middle class and fosters a society of winners and losers.”

As a result, more children grow up without the care and support of their mother and father—and it’s costing everyone: “The loss of social opportunity for these children and their families, and the national cost to taxpayers when stable families fail to form—about $112 billion annually, or more than $1 trillion per decade, by one cautious estimate—are significant.” As the report notes, economist Ben Scafidi and his team of researchers found that “if family fragmentation were reduced by just 1 percent, U.S. taxpayers would save an estimated $1.1 billion annually.”

The authors of the report don’t suggest giving up on policy, writing that “it is only with respect to marriage formation that the policy world seems to have decided that very little or nothing can be done.” This isn’t true, as my colleagues at the Heritage Foundation and others have promoted policies to strengthen marriage for quite some time, most recently Robert Rector’s special report, “Marriage: America’s Greatest Weapon Against Child Poverty.”

The various policy proposals in “The President’s Marriage Agenda” deserve more sustained attention and consideration than I can take here. But a few comments are in order. The authors encourage President Obama to embrace his position as “a cultural leader who can inspire citizens, especially young people,” because “if we are to strengthen marriage and families in America, ultimately this will happen because young people want to bond with one another and give their children the gift of their father and mother in a lasting marriage.” But how can President Obama stress the importance of fathers and mothers while supporting the redefinition of marriage to exclude sexual complementarity?

The report’s fourth recommendation, “End Anonymous Fatherhood,” notes that “the anonymous man who provided his sperm walks away with no obligation.” Although a relatively small percentage of parents “use sperm donation or similar technologies to get pregnant, the cultural power of the idea that it’s acceptable deliberately to create a fatherless child and for biological fathers to walk away from their children is real.”

The authors propose that the United States ban anonymity in sperm donation “and reinforce the consistent message that fathers matter.” But how does marriage policy reinforce that message if it redefines marriage to say that mothers and fathers—one of each—are optional for marriage? How does redefining marriage to include lesbian relationships not further incentivize the type of anonymous sperm donation and resulting fatherless children that the authors protest?

Regardless of your stance on redefining marriage, the report argues, you can “talk about gay marriage—and then talk about why marriage is important for the vast majority of people who identify as heterosexual and whose sexual lives quite often produce children.” But is this really true?

After all, it isn’t just the legal title of marriage that encourages adherence to marital norms. There is nothing magical about the word “marriage.” Instead, marriage laws work by embodying and promoting a true vision of what marriage is that makes sense of those norms as a coherent whole.

Redefining marriage would abandon the norm of male-female sexual complementarity as an essential characteristic of marriage. Making that optional would also make other essential characteristics—such as monogamy, exclusivity, and permanence—optional, as my co-authors and I argue in What Is Marriage? Man and Woman: A Defense. We show how this is increasingly confirmed by the rhetoric and arguments of those who would redefine marriage, and by the policies that their more candid leaders embrace.

I should note that I presented some of this evidence in this post last week at Ricochet, quoting LGBT leaders Andrew Sullivan, Dan Savage, Victoria Brownworth, Michelangelo Signorile, New York University Professor Judith Stacey, and University of Calgary Professor Elizabeth Brake, as they explicitly rejected traditional norms of marriage.

Indeed, the most interesting—and revealing—comments during my week at Ricochet  were from those who said marriage is simply whatever sort of interpersonal relationship consenting adults—be they two or ten in number—want it to be: sexual or platonic, sexually exclusive or open, temporary or permanent.

That idea sounds like the abolition of marriage. Marriage is left with no essential features, no fixed core as a social reality—it is simply whatever consenting adults want it to be. Some who see this logic, thinking that marriage has no form and serves no social purpose, conclude that the government should get out of the marriage business.

If so, how will society protect the needs of children—the prime victims of our non-marital sexual culture—without government growing more intrusive and more expensive?

Separating the bearing and rearing of children from marriage burdens children first and foremost, as well as the whole community. It’s the community that often must step in to provide (more or less directly) for their wellbeing and upbringing. A child born and raised outside marriage is six times more likely to experience poverty than a child in an intact family—and therefore welfare expenditures grow. So by encouraging the norms of marriage—monogamy, sexual exclusivity, and permanence—the state strengthens civil society and reduces its own role.

But marital norms make no sense—as matters of principle—if marriage is redefined. There is no reason of principle why emotional union should be permanent. Or limited to two persons, rather than larger ensembles. Or sexual, much less sexually exclusive. Or inherently oriented to family life and shaped by its demands.

If marriage isn’t founded on a comprehensive union made possible by the sexual complementarity of a man and a woman, then why can’t it occur among more than two people? If marital union isn’t founded on such sexual acts, then why ought it be sexually exclusive? If marriage isn’t a comprehensive union and has no intrinsic connection to children, then why ought it be permanent?

This isn’t to say that couples couldn’t decide to live out these norms where temperament or taste so motivated them, but that there is no reason of principle to demand it of them. So legally enshrining this alternative view of marriage would undermine the norms whose link to the common good justifies state action in the first place.

This highlights the central questions in this debate: what marriage is and why the state recognizes it. It’s not that the state shouldn’t achieve its basic purpose while obscuring what marriage is. Rather, it can’t. Only when policy gets the nature of marriage right do we reap the civil society benefits of recognizing marriage.

The future of our country, then, relies upon the future of marriage. The future of marriage depends upon citizens’ understanding of what it is and why it matters—and demanding that government policies support, not undermine, true marriage. Unfortunately, “The President’s Marriage Agenda” overlooks these questions. How successful can a “new conversation on marriage” be when its leaders can’t even say what marriage is?