How would the US government respond to an alien visitor?
Why would anyone assume that an alien visitor would report to the US government? "Take me to your leader" only happens in comic books.
If I'm an alien coming toward Earth for the first time (let's assume I'm on a friendly--or at least non-hostile--mission) how will I make contact?
Where will I decide to land? Would I prefer to land in an empty sector, or near an urban area?
What direction am I arriving from? If I come in over the South Pole, the Earth looks like a water world. I'd likely touch down in Hobart, Queenstown, or Capetown.
If I come in over the North Pole, the night sky is awash in city lights below the Arctic Circle. It would be hard to choose where to land.
If I come in over the equator, I'm much more likely to spot Singapore, Kuala Lumpur, or Nairobi, than any city in the United States.
It's hard to think of a set of circumstances that make it likely I'd choose Washington DC as my landing location.
Wherever I set down, the local news media and police will be my first contacts, because they will seek me out. Unless this is in a completely closed society, within five minutes there will be 50,000,000 tweets. There is no way any government could possibly contain this event. Not even North Korea.
Whatever the US government did would be totally irrelevant.