1) Although governments and laws play a role in God’s plan (Romans 13:1-7), the church is God’s ambassador. She extends across national boundaries, ethnic lines and cultural barriers.
2) God’s blessing and favor on nations is contingent on their obedience to him, and is never lasts forever even if they turn away. If America as society has turned away from God we have no reason to boast in our current status.
3) God is clearly blessing and using citizens of many other nations for his glory as well (S. Korea, China) why say America enjoys privileged status?
The bible teaches that we are to live as aliens in a foreign land. That means our national affiliations can never become part of our core identities the way our allegiance to the Kingdom of Christ should be.