"We're often told that the United States is, was, and always has been a Christian nation. But in One Nation Under God, historian Kevin M. Kruse reveals that the idea of 'Christian America' is an invention--and a relatively recent one at that. As Kruse argues, the belief that America is fundamentally and formally a Christian nation originated in the 1930s when businessmen enlisted religious activists in their fight against FDR's New Deal. Corporations...