Well, first of all everybody had to be checked so as to see whether they
have any contagious diseases that would prevent them from being
admitted into the country. Then, their backgrounds had to be checked so
as to prevent criminals and possible terrorists from entering the US.
Lastly, their numbers had to be limited so as to keep Americans from
rioting if they start taking their jobs and just general space, which
doesn't really belong to them yet.
