I also remember reading this essay ten years ago in, I think, *Time*:

>As Newsweek notes, these stirrings for the mainstreaming of polygamy (or, more accurately, polyamory) have their roots in the increasing legitimization of gay marriage. In an essay 10 years ago, I pointed out that it is *utterly logical* for polygamy rights to follow gay rights. After all, if traditional marriage is defined as the union of (1) two people of (2) opposite gender, and if, as advocates of gay marriage insist, the gender requirement is nothing but prejudice, exclusion and an arbitrary denial of one’s autonomous choices in love, then the first requirement — the number restriction (two and only two) — is a similarly arbitrary, discriminatory and indefensible denial of individual choice.

And so I’ve noticed that Charles Krauthammer confuses the fallacious slippery slope with strict logical implication. Just because society grants rights to gay marriages between *two* persons of adult age (even by the judicial fiat of legitimate constitutional interpretation–see the first ten amendments to your U.S. Constitution for details) does not imply anything about *three* or *fifty-three* persons of adult or other age. As Krauthammer’s otherwise silly piece points out, marriage rites are conventional and so don’t obey the kind of implicational structure he suggests they do:

>On the other hand, polygamy was sanctioned, indeed common, in large parts of the world through large swaths of history, most notably the biblical Middle East and through much of the Islamic world.

So he does realize that gay marriage does not imply polygamy (or polyandry) and vice-versa. The connection is not logical or causal but merely psychological. Krauthammer’s argument–though studded with n0t-that-there’s-anything-wrong with-thats–does little to camouflage its illogical appeal to simple prejudice.