If we do not "take care" of other countries (as in stop being world police, stop assisting in their problems like Clinton did with Ireland's Troubles, etc...) we would have their problems at our doorstep.

Also, there is definitely a subset of Americans that cannot stand by living well when others aren't, just because they other people were born elsewhere. This applies on all levels: Country, State, County, City, Neighborhood, block, house, etc.