Polygamy advocates are closely watching the progress of gay marriage. Legalizing polygamy is next.
It's a continuum. The question is, where is the end? Remember the German cannibal couple? At least the eaten one was involved "consensually". /sarcasm.
If there is an amendment in the Constitution saying that "marriage is between a man and a woman", there should be a following statement in brackets )"a" meaning one, not two or more).