Gay marriage OTOH is the imposition of an entirely unprecedented definition of marital relations, the implication being that America is abandoning one of the cornerstones of western civilization: the nuclear family.
Actually, the cornerstone of western civilization, indeed of civilization generally, has been the extended family, not the nuclear family, and while we indeed have been abandoning that institution for the nuclear family for some decades now, you have utterly failed to explain how gay marriage imperils family, be it extended or nuclear.