Yeah, I'm wiped from a good surf today too. It's hard to be aggro most anywhere, even semi-anonymously on the internets, when you are surfed out. I guess I'll concede that the unifying "party" is the party of greedy a-holes and that they are the ones that make much of the bad sh!t happen and their presence is evenly distributed across all political stripes although from my liberal point of view I would argue that more of them are right wing. That said, there are real differences between the political stripes and I don't think that should be discounted, even across the mainstream parties.
The societies that have warred in the past were the wealthiest (as far as I've read which isn't very far). The NW Coast from the Makah in NW Washington up to the Tlingit in SE Alaska was a bloody place mainly because everyone was well fed, damp but warm, and probably bored shitless during the winter. They had long-distance transportation before the Spanish arrived and lots of calm waterways to travel along. These people had art and other prized possessions including slaves all of which were worth dehumanizing an enemy over. I do agree and know that there are/were peaceful societies even where there was some wealth. But, I do think it's in the nature of some people to be greedy and if a society isn't set up to handle it, those people will become tyrants. I think that, somehow, our imperfect system does okay at handling the tyrants (for our comfort only though. This says nothing about the cost that the "developing" world pays to support us.)
Regarding plundering the poor, these days Maylaysia, Thailand, El Salvador, now Haiti, and to a lesser extent with each passing year China have cheap labor that we want and are willing to dehumanize those peoples in order to get it. The problem that we face is that nowadays it's so systematic that most of us don't have to get the dirt under our nails. I'll agree that the major political parties in the US aren't doing a damn thing to change this. Clinton played a major role in liberalizing trade and thus exporting work out of the US. If either party really cared about humanitarian efforts then a lot more aid would have flowed into Pakistan since the flood and the genocide in Sudan would have been addressed.
I think that many of us have egalitarian and cooperative sides and these are the things that keep us from breaking out into total chaos as a society. The nice Canadians are really good at this albeit in a frustratingly shallow way. Research has shown, however, that almost any person can be made to despise another group of people or individual persons if given the right stream of BS and if humanizing information is withheld. So, while we have innate capacity for cooperation, we also have innate capacity for tribalism and being divisive if certain conditions are met. Maybe that's where the focus should be -- toward quelling the primal greed.