Q9: Well, I think you have rephrased my last question in order to answer it in a way that sounds like your way is the way Protestants were thinking, and it was not. It was the way Trent was thinking. See: the fellows at Trent believed that the only way to rectify the error of Protestantism was to anathematize it and stand separate from it. Plainly: they called those who were Christians "not Christians" and demanded they be run off.
Consider in juxtaposition the WCF on the canon of Scripture, which anathematizes no one, yet makes a vigorous affirmation that their view of the limits of the canon is the one by which believers ought to abide.
In your view, why does the WCF (as one example) fail to demand separation from those who affirm the wrong canon of Scripture? Asked another way, how can one abide that the WCF does not demand separation from those who would call those who receive only the shorter canon "not Christian"?
A9: The problem with Frank’s understanding of the Reformation and the Reformed Confessions comes from reading them apart from their historical context. We must remember that the late medieval and late Renaissance period was a time when creeds and churches go together. Not only that, there was no such thing as the separation between Church and State. What one believes limits one to a particular ecclesiastical gathering and has implications whether one’s religion is approved or persecuted by the governing authorities.
In England in the time around the English Civil War, three religious factions were vying for supremacy: the Anglicans, the Presbyterians, and the Congregationalists. Whoever came to power would suppress the other groups. The Anglicans did that before Cromwell and after the Restoration, the Congregationalists did that under Cromwell, and the Presbyterians only did so sporadically in Scotland. The Reformers and Puritans did not have to place an anathema in their confessions; it was de facto practiced. The very idea of a national church, which symbolized the visible (not invisible) church in that country, had at its very heart the idea that all believers are to join the national church and those who do not are considered by the pastors in that national church to be not in the visible Church (at least the visible Body of Christ as present in the country).
Each faction in the Reformation used their confession as simultaneously the thing which binds believers and that which excludes those outside the Church. The multiplicity of confessions in the Reformation era led to the Reformed leaders comparing confessions and accepting in spirit (with minor disagreements to be sure) each other’s confessions to show that those believers in another place were not to be considered unbelievers. (In fact, the Westminster Confession was to function as a Confession of unity between the Scots and the British, should the Presbyterians proved victorious in England.) The Reformed Confessions therefore united true believers while excluding those to be considered outside the visible Church.
There is thus no need to commend separation since all the Reformers and their descendants have separated from the Roman Church. Moreover, they kicked out the radical Anabaptists and in that sense separated from them. The Puritans later separated from the Church of England because she refused to continue reformation. Lastly, the idea of Confessionalism subsumes the doctrine of separation into a more holistic doctrine where we are not merely told what to separate from but what to separate to.
As an aside, Trent in its format is merely following the practice of the Church through the ages like for example in Nicea or Second Orange. There is nothing problematic or ahistorical in her pronouncement of anathemas; the problem rather was that Trent condemned the Gospel.