The reality is that the confessional age assumed a close working relationship between church and state. Many Reformed confessions were produced by national churches that understood themselves as public institutions with a divine mandate to order the religious life of the people. Because of this, the civil magistrate was seen as responsible for maintaining the unity, purity, and public authority of the church's confession. The anomaly of the present day is that churches formed by free association rather than by national establishment continue to hold historic confessions while rejecting the confessional doctrine of the civil magistrate. This shift has consequences. In a voluntarist setting, a confession is no longer a public standard binding a whole people; it becomes a voluntary statement adopted by a self‑selecting group. And because voluntarist churches exist by voluntary association, they also feel free to revise their confessions whenever their own interpretation of Scripture changes. The confession becomes an expression of the community's current convictions rather than a fixed doctrinal constitution.
Scripture is the norming norm (norma normans). The confession is the normed norm (norma normata). This means that when we hold to a confession, that confession must still be regarded as a real norm, because it sets forth what Scripture teaches. It is not a second authority alongside Scripture, but a subordinate authority under Scripture. The confession functions as a judge over our interpretations and private readings because it expresses what the church has already determined Scripture to teach.
Trueman's point is correct, yet this does not mean what it meant in the confessional age. In the confessional age, confessions were not easily changed because the church itself was not easily changed. The church was an institution, not a voluntary association. It had continuity, stability, and public authority. A confession was a doctrinal constitution, not a voluntary statement. But in a voluntary church, if the church is "true to itself," the confession will change whenever the community's understanding of Scripture changes. The confession becomes an expression of the group's current convictions rather than a fixed doctrinal standard.
The only reason many traditional churches have retained stable confessions is because they are borrowing the institutional stability of the past. The past acts as an anchor against change; but it is an uneasy relationship, because the ecclesiology that produced the confession no longer exists.
I suppose my question is, Why wouldn't you have these things? Not that I want them, but I would like to know what principle is going to resist them. I suspect, again, it is a relationship with tradition that is resisting the change. In modern Bible translation the changes are more or less holding the tradition. The NKJV more so; the NIV, much less so. But, again, it is an uneasy relationship when the spirit of the community rejects certain parts of the tradition and insists on its right to be "true to itself."