I got to wondering about how and when a letter or package is entered in the mail system of another country, makes it's way to the US. Does a letter from England shipped by boat become US Mail half way across the Atlantic, When it leaves an English port or when it arrives at a US port. I know there must be some international treaties which govern this. But, I recently ordered a set of tools from Russia and there is already a USPS tracking number showing me the various Russian postal facilities that the package has traveled through. (2 so far) I tried looking on line for the information but Google keeps referring me to pages of links about job transfers overseas Bing and mozilla were worthless as well.
It seems kind of miraculous that a letter from a new found relative (DNA test) in Australia can make it so seamlessly to my mail box in Pennsylvania. Or that packages from India arrived in under two weeks. Perhaps the one single thing that most Governments around the world are doing right.