Christian Nationalism and Supercessionism

As the political rhetoric in the United States continues its descent into utter, irretrievable ridiculousness, the new label of the Left to describe Republicans is "Christian Nationalists". No one seems to be able to put their finger on exactly what a Christian Nationalist is, but hey, in the modern age you have to shoot first and ask questions later. I got to thinking about this label today in light of some of the theological things I've learned over the past few years and it seems to me that the idea of Christian Nationalism, if it even exists, grows in large part out of Supersessionism, that is, the idea that God has transferred his promises from Israel to the Church. More specifically in this case, it is the idea that somehow the United States of America is at the center of God's plan for the earth.