There is plenty, unless you are intent on staying on message. Why don't you begin by addressing Bill Donohue's point below:
"...there is a serious question whether non-practicing Catholics should be considered Catholic. By way of analogy, if someone tells a pollster that he is a vegetarian, but has long since abandoned a veggie-only diet, would it make empirical sense to count him as a vegetarian? Self-identity is an interesting psychological concept, but it is not necessarily an accurate reflection of a person’s biography."
That nonsense applies to all denominations.
This is about voter data, not whether voters are rigidly devoted and pure to whatever church they are members of.
The Catholic category is much more rigid and exclusive than the Protestant category, “Catholic” means members of that single denomination, of that single teaching, single culture, of people actually baptized into that church, and who still consider themselves as members of that church, which they are.
To be counted as “Protestant” they merely have to identify as Christian and not Catholic. They don’t have have ever to belonged to any church, or even be baptized, or they can belong to any range of churches or denominations, Black, Episcopalian, homosexual, Obama’s church, Southern Baptist, Lutherans, or whatever.