First, America is not a Christian country. It is a country with a veneer of Christianity. That Christian veneer was once thicker but now the varnish is disappearing. Second, everything is more complicated that these either/or scenarios.
At the same time, Marilynne Robinson is right—America is filled with fear. It is everywhere. The right fears the left, the left fears the right, the rich fear the poor, the poor fear the rich, the haves fear losing what they have, the have nots fear not ever having more, the dominant culture fears other cultures, the non-dominant cultures fear the majority culture, blacks fear whites, who fear blacks, the powerful fear the powerless, the powerless fear those in power.
We are a people of hope, of resurrection, of trust in a God who will withhold no good thing from those who walk uprightly. We should be a people who live passionately for and like Jesus in the midst of everyone else’s fear. We should be an oasis of peace in the dry desert of fear that dominates not just America but most of the world right now.
Be and bring the peace of Christ to the world around you. There is too much fear out there for Christians to fail in this grace.