The essential basis should be, what it once clearly was, the interests of the rooted population and their posterity, down through the generations: The continuity of Americans as a distinct people, (or peoples, as I am a States' Righter),friends to all humanity, to be sure; but distinct people who respect others & expect respect back, for the heritages and continuity of all distinct nations.
An American Immigration Policy.
Our population is already beyond what the Founders would have considered ideal. They, as most Conservatives valued the great open spaces; the room to get away from the urban hustle & bustle that even then plagued Europe. Our institutions depend in part on reflective people, able to sort out the intellectual wheat from the confused mental chaff of modern life.
The implication is that already there is a mindset of hostility.