Simplified, there are several groups of people in the United States: immigrants, people that forgot they once were immigrants themselves that want to close the door on others now that they have theirs, people and their descendants that were brought there against their will and Native Americans.

All of these groups have their own idea of what America should stand for and their lack of agreement is materializing in a societal schism that I don't believe can be bridged under a single political system.

And yes, America has a responsibility to Afghanistan, but mostly because they are one of the major forces behind the current mess in the first place.