I think people get a little carried away with this. I'd bet money that the average American cannot even describe the difference between Protestantism and Catholicism besides something facile like "they have a pope." There aren't even any Protestants sitting on the Supreme Court.
In a historical sense, it's very geographically dependent. Before states got rid of established churches, Virginia, for instance, established the Episcopal church, while Massachusetts established the Congregational church.
In a historical sense, it's very geographically dependent. Before states got rid of established churches, Virginia, for instance, established the Episcopal church, while Massachusetts established the Congregational church.