If you want to have open borders then there’s really nothing standing in the way of implementing it. Except that you would need to abolish all government welfare. Otherwise you would have every person in the world who’s quality of life is worse than the quality of life afforded a US welfare recipient (which is billions of people) moving to the US. Which would naturally destroy the country.
Modern USA was created by migrants. But when the country was being settled, those migrants were faced with having to either provide for themselves, or die. The US has also seen a lot of growth from continuing to import immigrants. But those immigrants were all selected based upon a relatively strict criteria to evaluate whether they would be providing value to the country.
Modern USA was created by migrants. But when the country was being settled, those migrants were faced with having to either provide for themselves, or die. The US has also seen a lot of growth from continuing to import immigrants. But those immigrants were all selected based upon a relatively strict criteria to evaluate whether they would be providing value to the country.