The Earth has countries that are all fighting against each other. Each has their own culture, and belief system. But, if a global effort was made to colonize the moon, and then populate it with people of all nations, the politics would have to eventually work out in order for the colonization to work. That is if armies were not brought into the picture.
While colonization of the moon will give our society vast opportunities for positive outlooks on our future, it will not guarantee an improvement between the states. While it would grant us the opportunity to cooperate, it would most likely serve as a deterrent. It would distract us, instead of actually solving our political disputes. Instead, we should explicitly and visibly address this problem.
From what I've heard about in history class, more land equals more power. The moon is land. Everyone wants land. If one area gets the land, other areas want the land. If other areas want the land, they might try to take that land.
I don't think this needs any further explanation...