Prior to the early sixties, the majority of immigrants were white europeans. The Dems noticed that they made good Republicans. They called a halt to immigration "to let new immigrants acclimate" the rest has been a study in how to use immigration to alter America in harmful ways. No, we do not do best when we mix as much diversity as possible into the melting pot. As Ann Coulter said, we have become some kind of weird sociological experiment where masses of people from undemocratic societies are expected to vote on how to run a republic. Common values strengthen, people who refuse to melt into the pot weaken...witness England and France with their muslim populations.