I am in favor of polygamy, as long as it includes multiple male and female spouses. I get confused about how much of a role the government should play in defining these things. There are implications for the government relating to benefits, inheritance issues and child custody (as Arcana XV pointed out) and taxation. If the government removed all definitions of marriage, then that may be the same as defining that anyone could marry. It may be better for the government to define civil unions forming incorporated entities with two or more adults that would be relevant for benefits, inheritance issues and child custody (as Arcana XV pointed out) and taxation. Then let the marriage stuff fall to the churches.