The deeply controversial, sometimes raucous marriage debate soon will be settled once and for all. Public opinion is swaying toward redefining marriage. And at the end of this month, the Supreme Court will hear arguments in two cases challenging state and federal laws that define marriage as one man and one woman.

The nationwide creation of same-sex marriage seems all but inevitable.

At least that’s what many journalists, pundits and activists would have us believe. But nothing could be further from the truth.

The national debate over marriage remains robust and important. In many ways it is only beginning. Whatever the outcome of the Supreme Court’s deliberations this spring, the only thing that’s inevitable is this: Americans will keep talking about the issue well into the future – and with good reason.

Appeals to “marriage equality” make for good sloganeering but sloppy reasoning. Every law makes distinctions; equality before the law protects citizens from arbitrary ones. Marriage equality demands knowing what marriage is.

Marriage exists to bring a man and a woman together as husband and wife to be father and mother to any children their union produces. Marriage is based on the biological fact that reproduction depends on a man and a woman, and on the social reality that children need a mother and a father.

Marriage predates government. It is the fundamental building block of human civilization. All Americans, not just conservatives, should respect this crucial institution of civil society. Indeed, 41 states affirm that marriage is the union of a man and a woman.

Government recognizes marriage because it benefits society in a way that no other relationship does. Marriage is society’s least restrictive means to ensure the well-being of children. State recognition of marriage protects children by encouraging men and women to commit to each other and take responsibility for their children. While respecting everyone’s liberty – nothing is made illegal by marriage laws – government recognizes, protects and promotes marriage as the ideal institution for childbearing and childrearing.

But redefining marriage to include same-sex relationships would further distance marriage from the needs of children. It would deny as a matter of policy the ideal that a child needs a mom and a dad.

Decades of social science show that children tend to do best when raised by a married mother and father. The confusion resulting from further delinking childbearing from marriage would force the state to intervene more often in family life, prompting welfare programs to grow even more.

In recent years marriage has been weakened by a revisionist view that is more about adults’ desires than children’s needs. Americans increasingly are tempted to think that marriage is simply whatever sort of relationship consenting adults want it to be: sexual or platonic, sexually exclusive or “open,” temporary or permanent.

Redefining marriage to exclude the idea that it is fundamentally related to the union of a man and woman would make emotional intensity the only thing left to set marriage apart from other relationships. Redefining marriage would put a new principle into law – that marriage is whatever emotional bond the government says it is.

No principled reason could be offered for why an emotional union should be permanent. Or limited to two persons. Or exclusive.

But marriage can’t do the work that society needs it to do for generations to come if the norms are weakened further. All of us who care about a thriving civil society, with institutions capable of limiting the state and its power, should be alarmed.

The cases before the Supreme Court provide an important opportunity for Americans to discuss three questions: What is marriage? Why does it matter for public policy? And what are the consequences of redefining marriage?

Americans have good reasons to conclude that marriage exists to bring a man and a woman together to be father and mother to any children they have together. All Americans have the freedom to live as they choose, but no one has the right to redefine marriage for all of us.

The future of our country relies upon the future of marriage. And the future of marriage depends not only on our understanding of what it is and why it matters, but on demanding that government policies support, not undermine, true marriage.