For those who dont know, polygamy (here defined as 1 man marrying many women, not a correct definition) was practiced by the early LDS church and discontinued in 1890, when the US Supreme Court declared the laws against it Constitutional. Even in places where polygamy is lawful and culturally acceptable, the LDS church does not allow it members to have more than one living spouse at a time.
One of the rather weak arguments against gay marriage is that it will allow for the easing of restrictions on other unlawful unions, such as those involving incest and polygamy. While I don’t believe this to be true, I believe there is the possibility of polygamy being allowed in the United States and the rest of the world, but not in the Church, from the following verse in Isaiah (Chap 4, Verse 1):
And in that day seven women shall take hold of one man, saying, We will eat our own bread, and wear our own apparel: only let us be called by thy name, to take away our reproach.
Before the 20th century, it was difficult, if not impossible, for women to be independant of men. In most places, they had no voice or consideration as people, which may have necessitated them to marry, even sometimes more than one to the same man, to be able to live and accomplish in the world. In the later 20th and 21st centuries, this has changed dramatically. Women have the ability and cultural acceptance to do whatever they want to do, making marriage a luxury rather than a necessity.
One of the reasons I have heard for same-sex marriage is in the ability to have the tax benefits given to opposite-sex marriages. In the case of polygamy, this would be especially true, as it would allow for men and women to have marriages in name and benefits only, no matter what their desire to cohabitate or even have sex within the marriage. Yes, I know that can happen now, but I was trying to make a point toward the scripture I cited, of more than one woman marrying the same man to remove their responsibility.
Do I have any idea how or when this is going to happen? Or even if? Nope. Its just one of those random thoughts.