Among the many mistakes one encounters frequently in the views of anti-immigrationists is the assumption, sometimes the explicit allegation, that immigrants are representatives of or even the dregs of the countries from which they come.
But immigrants, on average, are in certain important regards not representative of their countries of origin. They are self-selected as unusually willing to bear risk and take initiative, to work exceptionally long and hard, and to start businesses — firms that in many cases have risen to global importance.
In short, immigrants, far from constituting a net burden, amount to a bargain for the current American population. Every time a million immigrants enter the country, the average quality of people living in the USA rises.