Ryan T. Anderson and Robert P. George

Opinion contributor

A decade ago, President Barack Obama affirmed that marriage unites a man and woman. So did 45 states and the federal government. The only states to redefine marriage had done so through activist court rulings or, in 2009, legislative action. At the ballot box, citizens had uniformly voted against redefinition. A majority agreed with Obama.

Then, in 2012, Obama “evolved,” and the Supreme Court took cases involving marriage law. Nothing in the Constitution answered the actual question at hand: What is marriage? The court should have left the issue to the people. But in 2013, it struck down the federal definition of marriage as a male-female union in a 5-4 ruling.

The court also punted on a challenge to a state definition of marriage adopted in a 2008 constitutional referendum by which a majority of Californians — yes, Californians — overturned an activist court. Only in 2015 did the Supreme Court, breaking 5-4 again, redefine marriage for the nation, provoking four irrefutable dissents.

Same-sex marriage advocates told the public that they sought only the “freedom to marry.” Same-sex couples were already free to live as they chose, but legal recognition was about the definition of marriage for all of society. It was about affirmation — by the government and everyone else.

It’s unsurprising that once a campaign that used to cry “live and let live” prevailed, it began working to shut down Catholic adoption agencies and harass evangelical bakers and florists. This shows it was never really about “live and let live” — that was a merely tactical stance.

Family, marriage — redefined

While these were the early effects of redefinition, the more profound consequences will be to marriage itself. Law shapes culture; culture shapes beliefs; beliefs shape action. The law now effectively teaches that mothers and fathers are replaceable, that marriage is simply about consenting adult relationships, of whatever formation the parties happen to prefer. This undermines the truth that children deserve a mother and a father — one of each.

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It also undercuts any reasonable justification for marital norms. After all, if marriage is about romantic connection, why require monogamy? There’s nothing magical about the number two, as defenders of “polyamory” point out. If marriage isn’t a conjugal union uniting a man and a woman as one flesh, why should it involve or imply sexual exclusivity? If it isn’t a comprehensive union inherently ordered to childbearing and rearing, why should it be pledged to permanence?

Marriage redefiners could not answer these questions when challenged to show that the elimination of sexual complementarity did not undermine other marital norms. Today, they increasingly admit that they have no stake in upholding norms of monogamy, exclusivity and permanence.

Same-sex marriage didn’t create these problems. Many in America had unwisely already gone along with the erosion of marital norms in the wake of the sexual revolution — with the rise of cohabitation, nonmarital childbearing, no-fault divorce and the hookup culture. It was no surprise that many would then question the relevance of the male-female norm. Legal redefinition is a consequence of the cultural breakdown of marriage.

Monogamy is old news

But same-sex marriage is a catalyst for further erosion. Already, we see respectable opinion-makers mainstreaming “throuples,” “ethical nonmonogamy” and “open relationships.” This was predictable; we and others predicted it.

Something we didn’t predict are the headlines about transgender and nonbinary “identities.” A decade ago, few Americans had given much thought to the "T" in "LGBT." Today, transgender identity seems to dominate the discussion of sexuality and sexual morality.

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There’s a logic here. If we can’t see the point of our sexual embodiment where it matters most — in marriage — we’ll question whether it matters at all. Hence the push to see gender as “fluid” and existing along a "spectrum” of nonbinary options.

There’s a deeper logic, too. Implicit in the push for same-sex marriage was body-self dualism — the idea that we’re actually nonphysical entities inhabiting physical bodies, or ghosts in machines. That’s why the "plumbing" in sexual acts seemed not to matter.

True one-flesh union, the foundation of conjugal marriage, was thought illusory. What mattered was emotional union and partners’ use of their bodies to induce desirable sensations and feelings. Of course, two men or two women (or throuples or even larger sexual ensembles) could do that. But the logic didn’t stay with marriage. If the body is mere plumbing, then sex matters less than identity.

This has had tragic consequences, especially for children.

Children burdened by our mistakes

Nearly unthinkable a decade ago, certain medical professionals tell children experiencing gender dysphoria that they are trapped in the wrong body, even that their bodies are merely like Pop-Tarts foil packets, as one expert explained.

Some doctors now prescribe puberty-blocking drugs to otherwise healthy children struggling to accept their bodies. They prescribe cross-sex hormones for young teens to transform their bodies to align with their gender identities.

As part of a government grant-supported study, doctors even performed double mastectomies on adolescent girls — including two 13-year-olds.

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These changes weren’t grassroots movements. They’ve come from people wielding political, economic and cultural power to advance sexual-liberationist ideology. The change has been top down — from Hollywood’s portrayal of LGBT characters to business executives boycotting states over religious-freedom laws. Having lost at the ballot box over and over — even in California — activists found new avenues: ideologically friendly courts, federal agencies, big corporations.

Having secured a judicial redefinition of marriage, they pivoted to the “T,” with the Obama administration redefining “sex” to mean “gender identity” and imposing a new policy on all schools.

And having won government support, activists turned to eliminating private dissent. Former presidential candidate Beto O’Rourke wants to yank the tax-exemption of noncompliant churches. Megadonor Tim Gill vows to spend his fortunes to “punish the wicked.” Who are “the wicked”? Those who refuse to accept the new sexual orthodoxy.

All of us, including those identifying as LGBT, are made in God’s image, are endowed with profound dignity and thus deserve respect. It’s because of this dignity and out of such respect that the institutions serving the human good — like the marriage-based family — should be supported, not undermined or redefined. That basic rights like religious freedom ought to be upheld, not infringed. That a healthy moral and physical ecology — especially for children — must be preserved.

The “progress” of the past decade has exacted steep costs.

Ryan T. Anderson is the William E. Simon senior research fellow at The Heritage Foundation, and the founder and editor of Public Discourse, the online journal of the Witherspoon Institute. Follow him on Twitter: @RyanTand

Robert P. George is the McCormick Professor of Jurisprudence and director of the James Madison Program in American Ideals and Institutions at Princeton University. Follow him on Twitter: @McCormickProf