I - The Proposed Federal Amendment Banning Same-Sex Marriage Does Nothing to Protect Heterosexual Marriage (continued)C) It Does Not Close Pandora's Box
Many critics of same-sex marriage argue that if it is legalized, incest, polygamy, and bestiality will ensue. What they usually fail to point out is that the Federal Marriage Amendment doesn't actually ban incest, that laws pertaining to marriage and divorce could not be adapted to include polygamous unions, and that in cases of bestiality, one of the parties involved isn't human and therefore isn't covered by the Bill of Rights. And if the courts ever decide that dogs, cats, squirrels, and so forth are covered by the Bill of Rights, cross-species marriage will be the least of our worries.
In any case, the way to ban incestuous, polygamous, and half-bestial marriages is not by passing a constitutional amendment that bans same-sex marriages. It's by passing a constitutional amendment banning incestuous, polygamous, and half-bestial marriages. And unlike the Federal Marriage Amendment, that constitutional amendment would receive enough votes to actually pass.
II - The Proposed Federal Amendment Banning Same-Sex Marriage is Contrary to the Basic Principles of American DemocracyA) It Serves No Legitimate Secular Purpose
Most arguments against same-sex marriage ultimately boil down to the idea that the government should protect the "sanctity" of marriage, or that marriage is a "sacred trust" handed down by God.
But the truth of the matter is that the government has no business doling out sanctity and sacred trusts in the first place. Marriage, as far as the government is concerned, is and must be a secular institution. The government can no more hand out a marriage certificate that grants a sacred union than it can hand out a death certificate that grants a place in the world to come. The government does not hold the keys to the sacred.
And just as the government does not hold the keys to the sacred, it should not make decisions that are based on the premise that it does. If the purpose of the Federal Marriage Amendment is to "protect the sanctity of marriage," then it has failed in theory even before it has had the opportunity to fail in practice.
B) Full Faith and Credit Exists for a Reason
Article IV of the U.S. Constitution requires each state to recognize the institutions of other states. This article was not written to cover such institutions only in cases where there was no disagreement between the states as to the criteria, because those cases can be negotiated peacefully between states and require no federal intervention. No, the explicit purpose of Article IV is to ensure that, when states disagree, they do not invalidate one another's power to govern, dissolving the United States into a pre-federal confederacy with 50 states and 50 different systems of law.
So, yes, the Supreme Court--even a conservative Supreme Court--might find that a same-sex marriage performed in Massachusetts must be recognized in Mississippi. But isn't this exactly as it should be? If we set a precedent, even through amendment, that allows Mississippi to ignore Massachusetts marriages because the criteria for same are not specific enough, then we set a precedent for Massachusetts to attempt to do the same with regard to Mississippi marriages. Our federal system is one that forces us to get along--even when we disagree. The controversial topic of same-sex marriage should be treated no differently in this respect than any other controversial topic that has emerged in our country's history.