Polygamy is a detriment to a society. I'll start with the feminist objection, even though I know that most people like to shrug at that, in that when you set women at the level of objects, where a rich or successful man can have many, and collect them like fine cars... well, that puts women at subhuman status, and in this day and age, I find that unacceptable. But let's ignore that if you'd like, and focus on war and social unrest. Do you know what most of the most violent areas of the world have in common? Polygamy. Do you think it's coincidence that in areas where a minority of people have "snatched up" most of the women, leaving a good portion of the rest of the men without wives, that huge groups of these wifeless men band together and through war, acquire and rape women? I don't think it is coincidence at all. My last objection is that while Muslim doctrine says that a man should not marry more women than he can afford, it fails to specify. Afford what? To feed and clothe? That's a very different level of wealth than "afford to educate". So then you've got men that are successful enough to keep food in the belly of their family, but they've got 25 children, and not a single one can go to school on daddy's income. What's a good way to keep a perpetual war going? How about uneducated children growing up in poverty because of a lack of education, and then due to poverty, being not only unable to support themselves, but unable to get a wife, because the rich dude down the road has most of the women, and to top it off, there are actual passages in the holy book that say you can't have sex unless you're married.... UNLESS you acquire these women through holy war... in which case, force them to be your wives (aka: rape them). Long story short: Polygamy is the reason for much of the violence in the world today. I definitely think any intelligent, developed nation would be wise to not allow it.