Is Christian nationalism a Christian idea?

The entire notion of a modern nation state is a non Biblical idea, if we want to be literal about things. (Where in the Bible are Parliaments or Senates mentioned?)

The people of Israel were originally ruled by Judges.
Then they had Kings.
Then they were under the dominion of occupying powers: Assyrians, Babylonians, Romans, among others.

After the fall of the Roman empire, "Christendom" consisted of medieval kingdoms. The King was considered to be ruling by divine ordination. It was all part of the "natural order" of God's world.

In fact, the Church was opposed to the rise of "nationalism", as it was seen as an overthrowing of that natural order. (I am using the word nationalism in its original sense: the transition from kingdoms to modern-style nations.)

And of course, by no stretch of the imagination is the United States of America even hinted at in the Bible.

The "Christian idea" is that the Church is universal.

My own take is that images of "flag and cross", or "American eagle and Jesus" are bordering on idolatry. What are Christians from the rest of the world to make of those images?

As Andy Stanley , a pastor in the Atlanta area and son of TV evangelist Charles Stanley, says in his book Not in it to win it, "I do love my country. I love it deeply. But when I die, I am not going to Washington, DC. And neither are you."