The short one
the long one....
So who, exactly, is responsible for the US portion of this mess? To be blunt, there's no one person. There are lots of people involved, and several bureaucracies and agencies and organizations. There are people at the head of those groups, but no one person is responsible. Some groups are more responsible than other groups, but that's about as close to finger-pointing as I can get.
But you might imagine which groups I would list as "more responsible than other groups" :-)