[mc32]

As sovereign, countries can change their policies --as Western Europe did after WWII to attract a workforce to rebuild --and in the 70s once that workforce was no longer necessary.

Every country has a carrying capacity --the limits can be economic, resource-bound, land-bound, political, etc. Why would the US be any different?

The Statue of Liberty is a statue expressing an ideal albeit a bit troubling in that it assumes a world of poor huddled masses --but it's not a national policy.