The idea that the family is an institution at all is hard to deny and yet difficult to comprehend. This is in part because the family occupies a distinct space between two meanings of the term “institution.” It is not an organization exactly, but neither is it quite a practice or a set of rules or norms. In a sense, the family is a collection of several institutions understood in this latter way—like the institution of marriage and the institution of parenthood. The family arranges these institutions into a coherent and durable structure that is almost a formal organization. It resists easy categorization because it is primeval. The family has a legal existence, but it is decidedly pre-legal. It has a political significance, but it is pre-political too. It is pre-everything.

This is sometimes a real problem for our liberal society, because it casts doubt upon the idea that our natural state is some kind of libertarian individualism. Some important political theorists in our liberal tradition have tried to ground their ideal of liberty in a pre-social condition, or a state of nature, that is populated by wholly independent individuals. Yet these kinds of thought experiments, for all their value, are plainly implausible as descriptions of the human condition. No human being has ever lived a life in circumstances of utter individualism, without some degree of community—which often is at first an extended family. Our social order flows out of the basic conditions of how we come into the world, move through it, and depart it, and so it unavoidably flows outward from the family. Family is the most primordial, and therefore the most foundational, of the institutions that form a society.

It is also therefore, more than anything else in our experience, a form of our common life—a structure for doing essential things together. That is what makes it our most basic institution. But how is the form of the family related to its function? It is this seemingly straightforward question that has put the family at the center of our contemporary culture wars.

We know that people need thriving families to flourish. No one in any corner of our politics would really deny that now. But what are the needs that the family meets? Some are surely practical necessities: families care for their members’ material needs. They feed and house children (and at times the elderly or others) who would be unable to feed and house themselves. They enable the sharing of resources and responsibilities, so that everyone has someone whom they trust, and whom the larger society trusts, to care for them if they are unable to care for themselves. The family is also a vessel for our deepest loves: it is a formal acknowledgment of a set of human relationships.

These two facets of what the family does—serving as a means of provision and a means of recognition—are increasingly central to our contemporary understanding of the family’s function. But they leave out the family’s formative purpose, the ways in which it shapes our soul and molds our character. When we put aside the formative functions of the family, we might be able to persuade ourselves that thriving families are important only for economic and symbolic reasons—that so long as our material needs are met and our relationships are recognized, the family has served its core purposes. Where families prove unable to meet their members’ material needs, other forms of assistance, both public and private, can fill in the gap, and the family can just stand as an acknowledgment of mutual love among its members.

This would suggest that the form of the family, and therefore its formative potential, may not be essential to its function. But, of all our institutions, this is surely nowhere less true than in the family. The family is our first and most important institution, not only from the perspective of the history of humanity, but also (and more simply) in the life of every individual. It is where we enter the world, literally where we alight when we depart the womb. It gives us our first impression of the world, and our first understanding of what it is all about. It then sees us through some of our most vulnerable years of life, taking us by the hand as we progress from the formless ignorance of the newborn through the formative innocence of early childhood to the fearful insecurities of juvenile transformations and hopefully, eventually, to a formed and mature adjusted posture in society. This is a process of socialization, and therefore fundamentally of formation. But it is not a formation that happens through instruction so much as through example and habituation. The family forms us by imprinting upon us and giving us models to emulate and patterns to adopt.

The family does all this by giving each of its members a role, a set of relations to others, a body of responsibilities, and a network of privileges. Each of these, in its own way, is given more than earned and is obligatory more than chosen. Although the core human relationship at the heart of most families—the marital relationship—is one we enter into by choice, once we have entered it that relationship constrains the choices we may make. The other core familial bond—the parent-child relationship—often is not optional to begin with, and surely must not be treated as optional after that. It imposes heavy obligations on everyone involved, and yet it plays a crucial role in forming us to be capable of freedom and choice.

In this sense, the institution of the family helps us see that institutions in general take shape around our needs and, if they are well shaped, can help turn those needs into capacities. They literally make virtues of necessities, and forge our weaknesses and vulnerabilities into strengths and capabilities. They are formative because they act on us directly, and they offer us a kind of character formation for which there is no substitute. There is no avoiding the need for moral formation through such direct habituation in the forms of life.

In the family, this often means habituation in the roles reserved for spouses, parents, children, grandparents, and other supportive relatives. That means the form and structure of the family is essential to its ability to serve a formative purpose.

This is not necessarily good news, because family structure is not an easy thing to build and sustain. In fact, for the past few generations, our society has had enormous trouble doing both. We are plainly living through a collapse of family forms. About four in ten American children are now born into a family with only one parent—generally a single mother working hard to provide the resources, the structure, and the love and support her children need. Meanwhile, marriage rates have fallen, and married couples have tended to have fewer children over time. This has meant that family life in America has fallen away from the traditional pattern of family structure. That has happened for the most part without the emergence of a new or different durable institutional structure for the family, so it has happened as a deformation and has therefore been a source of disorder and disadvantage in the lives of many millions of Americans.

The model of the traditional family—a mother, a father, children, and an extended family around them—has always been a general norm more than a universal reality. It is important not because everyone has lived this way, but because even those who live otherwise (as, one way or another, a great many families always have) could implicitly resort to this model of the family as a baseline to understand what they possess and what they lack. Formation often involves patterning ourselves after what we seek to resemble, and the ideal of family built around parenthood rooted in a stable marriage has always served that role, even for many people whose lives are not so traditional.

It is precisely on this front that family life in America has been affected by the penetration of culture-war politics into every institutional crevice in our society. The family, because it unavoidably constrains personal choice and expressive individualism, has been turned into yet another arena for controversy in our multifront political and cultural struggle. The particular shape of the debates we have had—whatever one thinks about same-sex marriage, the rise of cohabitation, single parenthood, or any of the other family-formation controversies of recent decades—has often caused us to perceive an emphasis on the forms of families as an effort to deny recognition and legitimacy to some individuals. This has meant that the popular culture has recoiled from the importance of form in our understanding of family, so that we increasingly come to define family formlessly, or want to allow it to take any form that individuals choose.

This necessarily requires us also to attenuate our sense of the function of the family, or of its purpose. The family as an institution has gradually come to be understood less in terms of its form (and therefore its potential to serve as a formative influence on individuals) and more in terms of its chosen-ness (and therefore its potential to serve as a mode of expression and recognition for individual identities, preferences, and priorities). Thus, to a degree the family, too, becomes a kind of platform, a way of being recognized.

This cultural tendency has plainly been driven by a passion for inclusion, and has surely advanced that vital moral cause. It is far from nefarious, even where it has been detrimental, and it has by no means always been detrimental. But both by fanning intense controversy around marriage and family and by altering our expectations of both, this tendency has made it harder for us to understand the family as a formative institution and to approach our roles in our own families accordingly. Among other things, we have gradually come to treat the intense and nearly universal desire for family life more as a longing for recognition than as a hunger for order and structure, and that, too, has distorted our understanding of what our society and its members want and need.

In this respect, the winds of social change buffeting family life have resembled those that have affected many other institutions. Because the family is such a foundational institution, however, altered expectations of it must function as both causes and effects of the societal transformations we have been tracing. A diminished sense of the family as a formative and authoritative institution leaves us less prepared to approach other institutions with a disposition to be formed by them. And the loss of institutional habits up and down our social life—from government to the professions, the academy, the media, and more—leaves us more resistant to the sometimes burdensome demands of family life.

We face a crisis of family formation—evident especially in rates of single parenthood—but we have increasingly responded to that crisis by downplaying the significance of the family’s form. This is a way of avoiding the problem rather than addressing it. And it is deeply connected to our larger escape from institutions.

The family, perhaps more than any institution, forms us by constraining us—by moving us to ask, “As a parent, as a spouse, is this what I should be doing?” That dutiful question, which compels us to see ourselves as more than individuals performing on a stage, is the practical manifestation of the formative power of institutional authority. Its waning is a sign of serious trouble.

Yuval Levin is director of social, cultural, and constitutional studies at the American Enterprise Institute and editor of National Affairs. This article is excerpted from his new book, A Time to Build.