I'm sure somewhere in the vast cannon of FDA regulations there are standards for what can be labeled "wine" - a certain alcohol percentage, etc. And I'll bet there are more than a few folks on the Left who enjoy wine, and would be rather miffed if the courts suddenly forced the FDA to change its definition of wine to "anything anyone wants to put in a bottle and call `wine.'"
Yet that is exactly what the Left wants to do to marriage. If the government calls the union of two people of the same sex a "marriage," then on what logical or ethical basis can it refuse to sanction the union of three or more people of either sex? Or of two or more blood relatives of either sex? Or of any number of people of either sex plus one or more animals (of either sex)? The combinations are limited only by one's imagination.
At its core, the same-sex marriage movement is not about obtaining the few unique rights accruing to marriage. It is about intolerance of heterosexual marriage's existence and of its veneration as a social ideal. It's about using the Left's favored weapon of mass destruction, judicial fiat, to force society to provide the same veneration to homosexual unions. Anything less would be "intolerant" - their new definition of intolerance being "Failure to accept and celebrate a given behavior."
Focus on the Family has a quite comprehensive CitizenLink Extra on this subject, featuring detailed arguments on all facets of the issue and tools for contacting the relevant elected representatives.
(If you find this site useful and would like to help make political devotions a mass movement, please tell others about PoliticalDevotions.com or place a link to it on your website. Then when you've done so, be sure to e-mail me so I can thank you personally! - Tim.)