Rome's contention is that it is not possible to be catholic without be [Roman] Catholic. For whatever friendly advances Rome has made in the past years since Vatican II, the basic position of Rome has not changed much. Rome is the true visible Church on earth. Period. While it might be true that there are Christians outside of Rome, they rush to be in communion with the Pope once they realize their faith. Now someone will surely bring up the Orthodox, but Rome has an uneasy theological relationship with the Eastern churches and one that is beyond the purview of this particular meandering thought. Lutherans worth their salt do not surrender their claim to catholicity but they dispute to their very core the idea that this catholicity implies or requires reunion with Rome.
From Newman's suggestion that to be deep in history is to cease to be Protestant to the strange looks of those who encounter Lutheran claims to catholicity, the presumption is that being catholic automatically leads to being Roman Catholic. In this, both Rome and some Lutherans agree. For Lutherans who remind their peers that Lutherans are not sectarian nor are they Protestant are often quickly dismissed as Romanizers readying themselves to swim the Tiber. This is an inherent weakness of Lutheranism that taking our confessional, theological, liturgical, and sacramental identity seriously often raises the ire of those who are more content to see Lutheranism as the first Protestant sect. If you don't believe me, read some of the comments on my blog every time I mention things catholic.
Before the Church was “Catholic” she was already “catholic. Well of course this is true. But the contention of the Reformation is that the catholicity of the [Roman] Catholic was surrendered to novelties that were not and are not either catholic or ancient. Over and over again the Lutherans insisted that the articles of the faith in dispute were later additions and could not nor should they be allowed to bind the conscience of the believer. Whether or not you agree with the Lutherans, it has long been admitted that at best some of these doctrines existed as pious opinions along the way but became ordinary much later -- many perfected in medieval times. At worst, they were inventions that proceeded from and existed to support papal supremacy. Lutherans insist that the papacy is not central to catholicity (and may destroy catholicity) and in this the Orthodox readily agree.
Indeed, the challenge raised by the Lutherans is that what is essentially Roman is troublesome or worse for what is essentially catholic. Our complaint is not that the Roman Church is too catholic or Catholic but not Catholic or catholic enough. In this, the current occupant of the Chair of St. Peter seems intent upon proving our point for us. Far from being close to the charge of being Lutheran, Francis shows that what has become the center of Rome (instead of doctrine and practice) is submission to papal authority. This is what agitates against Rome's claim that to be catholic is to be [Roman] Catholic. For only in mythology can it be held that the papal office as it is defined and practiced today is supported by the ancient church. It is not even the development of a doctrine which is rooted in Scripture and tradition but the innovation of something neither Scripture nor the early church ever imagined.
There are many popes we might admire and many whose theological testament we would support but, for the Lutheran, it is a surrender of catholicity to admit that at the helm of the Church catholic lies the Pope. I wish, sometimes, we had a single voice to speak for us and a man to hold us as Lutherans accountable for what we confess and how we would practice that confession. But we do not. We have individuals to exercise the episcopal ministry among us (oversight of doctrine and practice) but we do not have an equivalent of the papal office. The Church is Catholic and catholic not because of the complexion of her many and diverse people but because she holds unwaveringly to the one, holy, catholic, and apostolic faith.