The Alien Inquistion Act was set during the creation of UNIT US in the late 80s by the current president at the time Ronald Reagan. It was created due to the mistrust of Extra-Terrestrials due to numerous incidents of invasions. Due to that any Extra-Terrestrial life on United States soil would be prisoned and expiremented on. The Act was passed and still stands to this day. Since then there has been only one Alien Ambassador for The United States that being The Doctor.