Lately the mainstream media has been rife with eye-rolling and heavy sighs in response to the conservative claim that the notion of same-sex marriage is a gateway to cultural decay. So I found a recent essay in The Economist refreshing for its frank admission that, okay fine, legally sanctioning  “same-sex marriage” probably does open the door to mainstreaming things like polygamy, logically if not politically.

That was maybe the only refreshing thing about the piece. The writer (“M.S.”) goes on to reassure  conservative readers that although institutionalizing same-sex unions leads logically to polygamy, it won't lead to a polygamous society in practice because historically monogamous societies have proven to out-compete polygamous ones.

Excuse me for not being comforted. If there’s an unbending law of economics preventing a people from adopting uncompetitive family institutional forms, a few societies apparently missed the memo. The ash heap of history is littered with vigorous civilizations that traded away their cultural capital for a mess of hedonistic porridge, gradually declined, and finally were overrun.

There’s another problem with the piece. M.S. tries to draw a consequentialist line between polygamy and same-sex unions by saying that polygamy is clearly bad for civilizational business, while same-sex unions fit nicely under the two-person umbrella of monogamy. But does anyone seriously think the strength of a nation can be found in a proliferation of same-sex partnerships, even if a sprinkling of these achieve a brave new fertility through in vitro fertilization?

The data isn’t complicated on the importance of intact traditional families to human flourishing. Education researcher William Jeynes’ summary of the accumulated findings offers a good thumbnail sketch of the state of the evidence. The California State University professor described the data connecting economic prosperity and the traditional two-biological-parent family as “immense,” and after reviewing several lines of evidence, explained that “the juxtaposition of these statistics with other facts indicates some of the reasons why there is such a strong relationship between marriage and economic growth.”

The plain reality is that nothing has proven as effective for raising up men and women equipped to compete in and contribute to society than the traditional, intact, monogamous family.

The final thing that struck me about The Economist piece was its innocence of natural law. Think about ancient Athens, arguably the pinnacle of ancient Western intellectual culture, and a thoroughly pagan society. Athens displayed an openness to erotic man-boy relationships that would rightly scandalize most of today’s same-sex marriage advocates. But that shockingly open society didn’t try to redefine marriage.

Instead, they apparently recognized, if only tacitly, that the institution of marriage is older than the state and has a reality apart from any word games somebody might wish to play with it. In other words, redefining a same-sex union as marriage doesn’t make it so, any more than declaring a circle a square gives it four sides. (The Athenians were good enough at philosophy and geometry to get this.) True, Athenian democracy was totalitarian enough to execute an innocent Socrates, but even they apparently understood that the state has to recognize certain limits.

So if you’re concerned about tax fairness toward same-sex couples, push our political leaders to streamline the tax code. If you’re concerned about the feelings of a gay friend or neighbor, buy him a latte and assure him that Jesus loves him as much as all the other sinners in the world (7 billion and counting). But don’t jump on the bandwagon of redefining the pre-political reality that is marriage, an institution firmly grounded in the natural order. Aiding and abetting a life of illusion is not compassion. And granting the state the power to redefine concepts older than the state is no sustainable formula for either justice or liberty.

[Jonathan Witt, Ph.D., is a research fellow with the Acton Institute and co-author of A Meaningful World (IVP). He has scripted three documentaries that have appeared on PBS, including The Call of the Entrepreneur and The Birth of Freedom, and three DVD curricula—two available from Zondervan and the recently released PovertyCure DVD Series.]