A Christian Nation?

Philippians 4
4 Always be full of joy in the Lord. I say it again—rejoice!5 Let everyone see that you are considerate in all you do. Remember, the Lord is coming soon.
6 Don't worry about anything; instead, pray about everything. Tell God what you need, and thank him for all he has done.7 Then you will experience God's peace, which exceeds anything we can understand. His peace will guard your hearts and minds as you live in Christ Jesus.
8 And now, dear brothers and sisters, one final thing. Fix your thoughts on what is true, and honorable, and right, and pure, and lovely, and admirable. Think about things that are excellent and worthy of praise.9 Keep putting into practice all you learned and received from me—everything you heard from me and saw me doing. Then the God of peace will be with you. NLT