I posted an argument here that the following three claims are incompatible with each other: the beatific vision was natural to unfallen man, the Church and State should be separate, and the State did not result from the Fall. We can retain the latter two claims only by denying the first claim. And this has soteriological implications regarding the disagreement between Protestants and the Catholic Church over the doctrines of the Fall, original sin, and ultimately, justification.
"Let unity, the greatest good of all goods, be your preoccupation." - St. Ignatius of Antioch (Letter to St. Polycarp)