Quote:
Whether multi partner relationships should be afforded the same rights as single partner ones is a huge question but to my mind it's difficult to see why the state should be involved in a group of individuals family structure. [...] I'm not trying to defend polygamy, just saying I can't see a case for government involvement in interpersonal relationships.

I suspect originally it was to encourage population growth, but nowadays it's probably more to do with relationships as support structures: in a marriage, if illness or unemployment or whatever strikes one partner, the other partner will do all they can to shoulder the burden. An unmarried person would end up being more of a burden to the state instead. So it's in the state's advantage to encourage these little support networks; IIRC, in the UK at least, members of religious orders enjoy some of the same tax breaks as married couples, probably because again the religious order is taking some of the support burden away from the state.

Which would tend to imply that, at least where the multi-partner relationship isn't more socially dysfunctional than it's worth (no constant stream of discarded wives), the state probably should promote it.

Peter