My one contribution to world thought, though someone has probably already said it, is this: There is no "we" without a "them." Conservatives need liberals; liberals need conservatives. Good guys need bad guys; bad guys need good guys. The righteous need sinners; sinners need the righteous. The actions of sinners might or might not remain the same if there were no righteous people to point the finger. It's the polarity that does the defining. One is not a sinner in a vacuum. One does something and it's a sin if someone has so defined it, and the definers do so as a contrast to their own position. Righteous people can't exist without sinners. Can you imagine a world full of righteous people (horrible thought)? They wouldn't be righteous because there would be no category "righteous," or perhaps even a concept "righteous." However, comes a sinner and zing! righteousness exists. And sinners need the righteous. How many people sin to punish themselves? Or to thumb their noses at society, parents, peers? If there were no righteous, what would they do? I remember being at a school that was so uptight that people who played Hearts (the card game) on weekends were suspect. The good thing about that is that one can be a rebel and not do any great damage to one's self. At a liberal school, you'd have to pierce some important body parts to be a rebel.
Let's extend this into the cosmos. When will the world become one people? When we discover intelligent life on other planets somewhere. Not until then. We've got to have the "them," you see.
One of our problems as an American society is that we really don't have a good, solid them out there. We're it - king of the hill, cock of the walk, cream of the crop (multiply cliches as needed). As long as we had the evil Commies, we could have some sort of unity. The Nazis unified us nicely, thank you. Who can step in and take their place? The mid-east? No, that's a family feud and we're only in it for the oil. Aside: Does anyone really think we'd care what the mid-east did to themselves if it wasn't for oil?
Bottom line -- we'll keep squabbling until ET comes to town and then we'll whip into line.