When I took ancient Church history in seminary, I had a hard time keeping all the heresies straight. (Not straightening out my own heresies: that's another story.) In historical theology, heresies are not identified by their doctrinal content, but instead by the names of the persons most identified with them. Therefore, instead of modalism (the belief that the three persons of the Trinity are not distinct, but instead are really just one person appearing in three different modes), we have Sabellianism. When I was asked to identify Nestorianism, Manicheanism, Arianism, Montanism, ad infinitism, I had to remember the historical figure, then remember what he taught, and then explain why it was wrong. While I have no problem explaining what's wrong with modalism, I'm not entirely sure what Sabellianism even is.
Since I've learned I can't fight the historical theologians, I've decided to join them and thereby go to my grave satisfied to have made life more difficult for future seminarians. Centuries from now, the twentieth century will be known for Diotrephesism, in recognition of him who desired preeminence and so would not receive the Apostle John (3 John 9).
In my opinion, at the root of many of the controversies which consume confessional presbyterianism today is the fact that in the 20th-century struggle with liberalism, presbyterians lost their sense of denominational identity along with a grasp on the historical and Biblical reasons for our distinctives. That absence has led to a sort of faddishness, in imitation of the sin of Diotrephes, which emerges in two different ways.
Certain elders (especially teaching elders) do not see themselves as guardians and teachers of the presbyterian tradition. Because many of them came to a reformed understanding of the Christian faith from other traditions, they see themselves as set apart by virtue of study and continue to seek to set themselves further apart by further study. These tend to maintain traditional worship practices, but the liturgy becomes merely a setting in which they can use the sermon to position themselves as experts on all things "reformed." Wishing to be preeminent in the eyes of their peers, they keep up with the latest theological controversies emerging from the seminaries and set these issues before their congregations as though they were as essential as the doctrines on which our Confessions focus. This obsession with “theology,” when it comes over and against a focus on the simple Gospel of the Cross, stokes up much furor on the interwebs and feeds division in the Church.
Others in leadership, who have never been taught why our traditions are our traditions in the first place, worry that presbyterianism is about to become irrelevant. These keep a watchful eye on the latest developments in evangelicalism and seek to imitate them while keeping the preaching Calvinistic. In these circumstances, members are deprived of the riches of our presbyterian inheritance and the blessings of catechetical instruction. As evangelicals drift ever further into worldliness (in all its forms), this group may drift right along with them.
The discerning reader will observe that this faddishness does not necessarily lead to heresy, but it certainly produces division. Athanasius fought the heretic Arius with Biblical doctrine. In imitation of John, the beloved disciple, we must fight Diotrephesism with Biblical charity.
I believe we should respond by learning our confessional standards along with our government, discipline and worship, and the Biblical warrant for them. I believe we should be extremely careful in preparing men for ordained office and not be too hasty to lay on hands (1 Timothy 5:22). I believe we should strive to present and live out presbyterianism for what it is: the most Biblical form of the Church and the one which should most demonstrate to the world the Church as our Lord formed her to be.