I'm interested in economic, political, geographical and ideological influences on the Party Centre's Xenophobia and romanticisation of the peasant class, and how that led to the Cambodian genocide. I'd also appreciate knowing about the US's policy regarding the Khmer Rouge, and what effect that policy had on later events. Thanks!
I am, unfortunately, too busy with research/writing to give you a specific response to this but you might find some previous answers helpful in the meantime! Or you could check out this talk by Phillip Short who wrote a very good biography of Pol Pot here
What led to the rise of Pol Pot
What were the reasons and consequences of intellectual killings
Links between Buddhism and CPK ideology
These don't touch particularly on US policy but the influences on the party's ideology is detailed in a few of them and the comments.
In a couple of weeks I might have the time to write you a detailed response that answers your particular question. In the meantime maybe you want to check out the podcast 'in the shadows of utopia' which looks to explain the Khmer Rouge revolution in the context of Cambodian history.