You would be surprised. Entire churches have converted to Catholism. Remember that George Washington’s church (Episcopalian) was part of the reason our founding fathers left Europe. They wanted to be able to worship without undue worldly influence. Traditinal faiths have much more in common with Catholics than “non denominational” churches. Not one of our founding fathers was a Southern Babtist.
http://www.huffingtonpost.com/2011/06/06/maryland-episcopal-roman-catholic_n_871950.html
Not surprising, since Southern Baptists didn’t split off till the slavery issue became dominant.