John McGuckin's assessment, in his magisterial work on St. Cyril of Alexandria and the Council of Ephesus, was that Nestorius was not really Nestorian. That is to say, Nestorius did not teach a doctrine of Two Sons, where Christ was both a fully Human person and a fully Divine person. The technical language of person did not quite exist yet, but principally, the Syrian church, with such luminaries as Theodore of Mopsuestia, taught doctrine that came close to saying that there was a functioning dualism in the life of Christ. It was not adoptionism, where Christ was a regular Human who, on account of His life, was granted divine privilege and/or status, but Two-Sons doctrine took on certain elements of it. It held that there was some sort of coming together of the fully Human Jesus, and the divine Word. This doctrine was never fully embraced, though it was skirted around and implied quite frequently, and therefore the obvious flaws (e.g. how is the one Christ not schizophrenic? How do the two relate? Was there a moment when the Human Jesus was without Divine Word? Is that conceptually possible?) were never ironed out. Since the technical language of person, whether hypostasis or prosopon, was not developed, these debates have a strange flavor when looking back.
Nestorius was a Syrian who succeeded to the office of archbishop of Constantinople, and carried his theological training with him. Constantinople was still theologically undefined, there was no "Byzantine" theology in the 5th century. However, because the Emperor of the surging Eastern Roman Empire resided there, it took on an artificial importance. Unlike other ancient sees, such as Rome or Alexandria, which gained its authoritative influence through a well established church, brilliant teachers, and blood of their martyrs, Constantinople was decreed influential through Church council. Thus, it did not develop its own unique brand, and because of its sudden rise to power, became a contested ground between other theological schools (e.g. Greco-Rome, Asia Minor, Egypt, Syrian etc.).
However, just because Nestorius was not Nestorian, does not mean he did not deserve condemnation. McGuckin is Russian Orthodox, and his colors show occasionally in the work. But the point he makes quite well is that Nestorius was not a helpless victim before the ecclesiastical politics of Cyril. Rather, Nestorius was brash and arrogant, and his main problem was that he sneered upon common people. Nestorius taught a doctrine that was hard to understand, unless you follow carefully the twists and turns of his logic. And this was something he was proud of, he did not think theology was something that belonged to the prols, but something for the well-educated.
The basic crime of Nestorius was that he introduced a split between the liturgical life of the Church and its dogmatic center in the teaching authority of her elders. The former was a residue of the latter. Thus, when Nestorius wanted to banish the grammar of Theotokos, Mother of God/God-Bearer, from the liturgy in describing Mary, he did not intend to give proper explanation. The phrase Christotokos, Mother of Christ/Christ-Bearer, was more fitting for Nestorius' system, which wanted to keep a strict division between the created and the Creature. Nestorius' primary concern, reflecting his Syrian origins, was to not diminish Godhead with the taint of creatureliness. Calling Mary the Mother of God sounded like Pagan myths, with gods who dwell among men and act like men. However, when it came to dealing with the facts of the Incarnation, Nestorius struggled to keep the Divine and Human together.
It was his convoluted theological system that the many unlearned bishops at Ephesus struggled with. Nestorius wanted the council to be a scholastic debate, where he expected to easily crush Cyril and condemn him as a Sabellian. However, Cyril had attempted to make this a catholic debate, where as many bishops throughout the world could attend. In these days, most bishops were not much more than the local pastor of a village. They were still many times chosen from the local area. For the well-heeled Nestorius, he was offended by the dozens of Egyptian and Asian bishops who had little formal education and some who were illiterate. Contrary to myth, this was not a battle between the distraught Christian bishop and the legion of quasi-Pagan pastors from the countryside. This is an elitist story, assuming that the schools of the city made better Christians than the rural hicks who passed on their training at a personal and communal level. Rather, it was a mass of perplexed pastors who could not grasp Nestorius' nuances, who he began to grow increasingly frustrated with. Yes, the council involved underhanded politiking. It's not clear why the Syrian delegate never arrived to bolster Nestorius, whether Cyril was trying to crush Nestorius with a consensus he forged, or if the Syrians were trying to run out the clock, and purposefully delayed. Nestorius promoted the former account, while Cyril pleaded the latter.
The main hinge of the debate involves a question of "sound words". Nestorius was rightly condemned, not in spite of his doctrine but because of it. The problem with Nestorius is not exactly about glorifying Christ indirectly through His mother. Rather, it's about the relation of theology to the life of the congregation. Should theological formula only make sense to the educated, those who go to schools? Or how should liturgy and worship reflect the common faith of all, both the ordained and the lay? What is the role of the teacher in the congregation? He is the public defender of the common faith, or does he hold the keys to the actual truth that lies behind the strange, possibly barbaric, words of the vulgar grammar employed in the liturgy? Nestorius is a perfect example of Clericalism, and his controversy opens a debate over the teaching office in the Church.
I generally like Carl Truman, both as a historian and a Christian teacher. But I was highly disturbed when he conceived his role as teaching elder as keeping to the Westminster Catechism, which was not a standard that the congregation was held to. I'm not accusing him of clericalism, but there was a shadow cast. It seemed that there was the true doctrine which the ordained held, and there was a lower bar for the congregation. The former could only be grasped through formal education, and thus helps prop up the Seminary-Educational complex; the latter was for the common peoples. Milton said that Presbyter is Priest Writ Large. This approach sounds little different than the moral tiers of Rome, between the monks who obey the Councils of Perfection and the lay people who are given a lesser, more reasonable standard. There is much about the Westminster Confession which is unintelligible to those uninitiated into the complexities of Reformed dogmatics, and barely reflects the worship of the congregation. Perhaps the most grievous problem with moving a doctrine of election from a doctrine of salvation to a doctrine of God is that it fundamentally annihilates an impetus to worship. I've heard song about God's glorious choice of us for salvation, but I've never heard a rousing song about God electing the saints in eternity past in His inscrutable councils.
Nestorius ought to be a warning for all theological discourse. The role of the teacher in the Church is to be of, not above, the Congregation. The common faith of the Church is exactly that, common. The problem is not schooling or education, the problem is that the seminary has become a part of a caste system. Reformed circles can be worse than Rome in creating a dividing line between preacher and congregation, where an intellectual indelible mark is placed upon the ordained. This ought to govern how we think about doctrines of God (especially the fact of Triunity), doctrine of salvation (and thus the meaning of election in the drama of salvation), among many others. If for nothing else this is why we should give honor to that great Cyril, for he remains a firm shield against attempts to divide the congregation. For all his pesonal faults, his legacy speaks to the role of bishops being one of, and among, the people that they lead in worshiping our only hope, Christ Jesus, the savior of the world. Amen.