I boldly put this bald question to the President of the Victorian District of the Lutheran Church of Australia at a gathering yesterday. Not half an hour later, someone asked it of me. I wasn't meaning the unity of all Christians, just the restoration of unity between the Catholic Church and the Lutheran Church of Australia.
It is a modest hope. Modest because the LCA is a tiny independant church, without any administrative connection to any overseas body, doctrinally conservative, proudly scriptural, liturgical etc.
From our point of view it would require the LCA to acknowledge the the primacy of the Bishop of Rome. I am not too sure to what extent the "jurisdiction" of the Bishop of Rome would apply - certainly no more than it does in the Eastern Rite Churches (I have a theory that since Vatican I was formulated in a context where there was no recognition of any "true local churches" outside the Catholic Church, "universal jurisdiction" meant something different then from what it means today).
Then there is the problem of invalid orders. It is possible that such recognition and desire to enter into communion with the Holy See would on its own have an automatic "validating" effect upon the orders of the LCA. If not, reordination may be required for Lutheran pastors.
Also, the LCA would need to decide upon and commit itself to a particular liturgical "rite", which would be foundational to being approved by Rome. The current liturgical laissez-faire would have to go.
But most seriously, what would be required would be the will to enter in full communion. Here would be the real sticking point. For it is almost certain that were even a sizable proportion of the LCA open to entering into full communion with the Catholic Church, another sizable proportion would oppose it such that there would be a split among Lutherans in this country.
And that is a universal problem. It applies to any body that might want to restore the communion, especially the Orthodox. Were the Ecumenical Patriarch tomorrow to declare full communion with the Bishop of Rome, you can bet your bottom dollar that most Orthodox would instantly declare themselves out of communion with both.
One body to whom this does not apply is the Traditional Anglican Communion, a group united in its desire to enter full communion with the Catholic Church while retaining its own identity and rites. And,
according to this report on Marco's blog, it looks very much like it is going to happen.
If it does, then we are indeed looking at an interesting situation. The first Western Rite/protestant background ecclesial communion received in this manner. It would surely pave the way for other groups, especially as the liberal/conservative split within confessional bodies becomes more and more a reality.