Redefining marriage, as argued in this space yesterday, will undercut its public purpose and social function, causing great social harm. So, in the wake of last month's Supreme Court rulings, where does the marriage movement go from here?

Many have been keen to point out that the Supreme Court refused to redefine marriage for the entire nation. The Court refused to manufacture a constitutional "right" to same-sex marriage.

Citizens and their elected representatives remain free to discuss, debate and vote on marriage policy in all 50 states. They still have the right to define marriage in civil law as the union of one man and one woman.

Justice Antonin Scalia's dissent, however, tells us to be clear-eyed: "I promise you this: The only thing that will 'confine' the Court's holding is its sense of what it can get away with."

If it is clear that Americans are engaged in this democratic debate and care about the future of marriage, then the Court will be less likely to rule in an overreaching way again to remove the authority to make marriage policy from the people and their elected representatives.

First and foremost, defenders of marriage as the union of a man and a woman need to start living out that truth. Long before we had a debate about same-sex anything, far too many heterosexuals bought into a liberal ideology about sexuality that makes a mess of marriage — with cohabitation, no-fault divorce, extra-marital sex, non-marital childbearing, pornography and the hook-up culture all contributing to the breakdown of our marriage culture.

So the first thing to do is for husbands and wives to be faithful through thick and thin, till death parts them. Mothers and fathers must take their obligations to their children seriously. The unmarried must prepare for their future marital lives, so they can live out the vows they will make.

At one point in American life, virtually every child was given the great gift of being raised to adulthood by the man and the woman who gave them life. Today, that number is under 50 percent in some communities. Same-sex marriage didn't cause this sad situation, but it does nothing to help and will only make things worse.

After all, redefining marriage to make it simply about emotional companionship sends the signal that moms and dads are interchangeable. Redefining marriage undercuts the rational foundations for the norms of marriage: permanence, exclusivity and monogamy.

The second thing to do is to insist that the government respect those who continue to stand for marriage as the union of a man and a woman — and to insist that government not discriminate against them. Policy should prohibit the government or anyone who receives taxpayers' money from discriminating against them in employment, licensing, accreditation or contracting.

When he "evolved" on the marriage issue 14 months ago, President Obama insisted that the debate was legitimate and there were reasonable people of goodwill on both sides.

He said those who believe marriage is a man-woman union aren't "mean-spirited" but instead "care about families." The president added that "a bunch of 'em are friends of mine ... you know, people who I deeply respect."

But sadly, we already have seen that many of those who favor redefining marriage are willing to use the coercive force of law to marginalize and penalize those who hold the historic view — even if it means trampling First Amendment protections of religious liberty.

Third and finally, we need to redouble our efforts to explain what marriage is, why marriage matters and what the consequences are of redefining marriage. The Left wants to insist that the redefinition of marriage is "inevitable." The only way to guarantee a political loss, however, is to sit idly by.

We must develop and multiply our artistic, pastoral and reasoned defenses of the conjugal view as the truth about marriage, and to make ever plainer our policy reasons for enacting it.

- Ryan T. Anderson is the William E. Simon Fellow at The Heritage Foundation and co-author, with Sherif Girgis and Robert George, of the book "What is Marriage? Man and Woman: A Defense."