I will guess that for 99% of Man's evolutionary past, that man, woman, and kids was not the typical way children were raised. Just looking at contemporary hunter-gatherer societies (what's left of them) shows one that. Many different kinds of arrangements have been used.
I will guess that what worked for hunter gathers where everyone knew each other and were typically closely related is not what I was referring to as "society". I doubt their society tolerated those who prey on children with much less than banishment or death. Whereas our leftist leaderships seems to invite them over our borders lately. see this is the thing ricter... not matter how much bullshit the left can put out on this issue -- a man and women raising their kids is logical unit that society should support.
Polygamy is quite common in the middle east. The koran has a lot of rules about it, eg the wives have to be treated equally etc. Frankly, I think it might not be a bad idea here. In europe and asia, it is almost accepted that married men will keep mistresses. Here the court system and man-hating feminists will gleefully ruin your life if you are caught out. Of course, the koran doesn't allow women to take multiple husbands. Some men would be ok with that, others not so much.
The state can have logical arguments against polygamy: Social security, inheritance, child supports.etc... If in polygamy there is no upper limit to how many persons one can marry, should the state (or employer) provide for all those spouses? Or just for the first one? Pensions and such. Inheritance problems: The dead man had 2 wives, one for 20 years, the other for 2 weeks. How does the law make a difference between them as inheritance goes? How about divorces and having multiple kids for multiple spouses? Who gets what? etc.etc. The husband is on life support, no medical will, 1 wife wants to turn the machine off the other keep it on....
I am not seeing that list adding anything new to the situation. By adding a gay spouse - the state or the federal govt or or private insurance company may have to provide benefits to a person they did not have to payout to prior? If it ok to expand it for a gay person... why not a plural marriage person? Isn't that arbitrary line just discrimination?
I got no problem with polygamy so long as people dont expect tax advantages, otherwise whats stopping an entire block from "marrying" each other? As has already been said, the government should just stay the fuck out of it to begin with.