So, you mean everyone except the native Americans should leave America? Just trying to understand clearly the implications of what you're suggesting :P
In all seriousness, after all this time I would bet most people couldn't trace a lineage to a single country now anyway.
They probably couldn't. And Europe being what it is, a bunch of them would have lineage going back to a country that no longer exists, i.e. if they were of any of the states that were ultimately absorbed into unified Germany in the 1800's.
It's all arbitrary. But we know damn well Trump and his goons don't mean "white" people when they say "immigrants."