I have never heard the term "white-adjacent' but then I've been mostly out of the country since 1972.

You ask whether America's core identity is white? It was and that's why the current MAGA movement is so virulently racist. That section of the country wants a return to those days when the country was more or less completely dominated by the white majority. The demographics have changed so much that that is no longer possible but like any reactionary movement they have become fiercer in their resistance to change as those old power structures will never return.

As to Anne Coulter, her father is working class Irish Catholic so her admiration for WASAPS is misplaced. Sounds like some form of Stockholm syndrome she must have picked up at Cornell.