With all due respect, the fact that the Bishop of Rome is the unifying principle is exactly the problem. The truly unifying principle is the Spirit of Christ, Who rules earth from heaven, not Rome. Christ did not send a vicar but His Spirit. Worship centralized on earth was judged forever in AD70. Men tried it once again in Rome, and again the wineskin was burst. True catholicity will always tear the veil, always transcend the highest walls of men, whether they be Roman or Protestant. And that is exactly our blessed hope.

Some may say that Roman Catholic then is an an oxymoron, but it is not. The “Roman” in the phrase does not modify the word “Catholic” rather, it merely identifies the unifying principal of Catholicism – the Bishop of Rome. Besides, the term “Roman Catholic,” is one that was employed as a pejorative by the Protestants, it is not our “official” name, and is not used by Catholics to describe our catholicity, rather it is used simply because that is how our Church is commonly referred to by the general public.

http://biblicalhorizons.wordpress.com/2012/05/25/one-holy-catholic-and-apostolic-church/

http://www.calledtocommunion.com/2012/05/too-catholic-to-be-catholic-a-response-to-peter-leithart/