When I think about White I also think about Railroaded: The Transcontinentals and the Making of Modern America and his remembrances of his mother in Remembering Ahanagfran: A History of Stories.
I don't normally think of Richard White as a historian interested in the idea of America as a "Christian nation." That is why I was surprised to run across his Boston Review review of Steven Green's Inventing a Christian America: The Myth of the Religious Founding and Kevin Kruse's One Nation Under God: How Corporate America Invented Christian America. It's a great review. Here is a taste of his conclusion:
Viewed over the longue durée of three centuries, the idea of a Christian nation traces our changing religiosity, but more interestingly our sense of ourselves. Like originalist constitutional interpretation, the appeal of the Christian nation lies in its assertion that nothing has changed; we are who we were in the beginning and will presumably be until the end of time. Except of course we are not. We are certainly not a Christian nation. Over three centuries we have had three chances to enshrine that belief in the Constitution, and each timewe refused.
And yet there is no denying the enduring influence of the idea. It is a way of linking an enduring secular providential strain of American thinking—that we are a chosen repository for the fate of all mankind—to a beneficent deity. When, at various times in our history, we did not have a clue as to what we were doing, it was good to believe that God did. And since we are a democracy, and the majority of us have been in some sense Christian, that God must be a Christian one. But attempts to be specific about God’s identity and plan lead to trouble. On those occasions, as Kruse writes, it becomes all too apparent that the United States is “not, in any meaningful sense, ‘one Nation under God.’”