What effects has US foreign policy had on other nations?

In talking about the Iraq war with my conservative (whatever that means anymore) friends, I keep stumbling across issues involving US foreign policy and its effect on the rest of the world, particularly third world nations.

I suspect that US economic and political policies have contributed greatly to global poverty, war, and hunger. I have some evidence that this is the case (our “foreign aid” propping up violent and oppressive governments, for example).

Can anyone make or point me at some solid arguments for this (or against it even, if it helps clarify the issues and then makes an obvious mistake). I’d like to be able to argue for why this is the case with more confidence and information than I have now.

Thanks in advance!