I've reflected a few times on my ambivalence as a Christian to gleefully endorse my country around patriotic holidays (see here and here). I read a prayer this week that aligns with much of what I think the church should be focused on when it comes to faith and nationalism:
God of Reconciling Love, We thank you for your reconciling mission, which is always inviting us to live in our mutual need of one another even before we recognize it. Teach us to love and to receive one another as Christ receives us. Amen.