For many critics, Constantine gave a Judas kiss of death to the Church. By recognising the Lord Jesus Christ and His Church, whatever his motives, Constantine seduced the Church to a life of worldliness. Pleasing and serving the emperor and his empire became ultimately more important than serving King Jesus.
Folk who think thus usually believe the Church is the most healthy, powerful, and spiritually vibrant when it is living under the Cross, under persecution, and under oppression. At such times we are truly following Jesus, truly walking in His steps. Rather than being conformed to this world, we are being conformed to the eternal Kingdom of Christ Himself.
The suffering church up to the third century AD was closer to Christ than the Constantine-adulating Church of the fourth and fifth centuries. Or so the story goes, we're told. Peter Leithart [Defending Constantine: The Twilight of and Empire and the Dawn of Christendom (Downers Grove, Illinois: IVP Academic, 2010)] has a different view, more profound and more biblically faithful.
In the first place, Leithart takes seriously the commands and responsibilities of the Great Commission. If we are to make disciples of all nations what would that look like? It would mean that all the commands of Christ (that is, as He speaks throughout the whole Bible) were being not just announced to the nations, but that the nations were being conformed and made obedient to King Jesus. Whilst the recognition of Christ and His Church by Constantine in 313 and following created lots of problems, temptations, and blind alleys it cannot be rejected as something sui generis with respect to God's Kingdom.
Secondly, the Church of the time celebrated the cessation of persecution and saw Constantine as an answer to prayer. God had heard. He had had compassion. And He had delivered His people. Such a response comes straight out of Scripture itself, whether one considers the Exodus, the Exile, the days of Ezra and Nehemiah, or the time of Queen Esther, or many other examples. The strange theory of purity through perpetual persecution implies something different: a more faithful Church would presumably have prayed for the removal of Constantine (and his temptations) and a return to Diocletian and the horrors of sacrificing Christians to the gods. Such flagellation is no enemy of the flesh: quite the opposite. It inflames the flesh with all its vainglory and pride.
But if Constantine and his christianised empire were so inconsistent and weak in many ways (and they were) what was the point? What positive interpretation can be given? Leithart argues at least two things are important. Firstly, Constantine accomplished the baptism of Rome. He astutely observes that baptism is always infant baptism, a baptism of children (whether adults or actual children) who have to grow into maturity. Constantine's baptised Rome was not an end, but a beginning of Christianisation of the empire. Consequently, inconsistency, weakness, and incompleteness are to be expected.
Secondly, the mode of baptism employed by Constantine was the removal of sacrifice in the Roman Empire. Leithart writes:
Constantine began to eliminate sacrifice from Roman life, and this was no mean achievement. Roman sacrifice was at the center of Roman civilization. It was the chief religious act by which Romans communicated and communed with the gods, keeping the gods happy to Romans could be happy. Sacrifice disclosed the secrets of the future, as the haruspex read the entrails of the slaughtered animals. Sacrifice was essential to Roman politics . . . . By sacrificing for or to the emperor, [Romans] acknowledged him as Lord, Savior, Deliverer, even, at times, as God. Christians refused because they knew there was another King, another world Emperor who filled that role, and Romans tried to suppress this Christian rebellion by sacrificing Christians. . . . Sacrificial slaughter in the arena was one of the empire's chief entertainments.It was not the beginning. Nor was it the end. It was the end of the beginning of the Christianisation of the Roman Empire. Much much more remained to be done. If we consider Constantine's contribution in that way, criticisms and exposure of inconsistencies and weaknesses of his Christianised reign can be seen for what they are: unfair and inappropriate.
Through Constantine, Rome was baptized, and sacrifice in all these senses came to an end or began to. Constantine stopped the slaughter of Christians. He refused to sacrifice at the Capital during his triumph in 312. He ended sacrifice for officers of his empire, thus opening imperial administration to Christians, and eventually outlawed sacrifice entirely. . . . He stopped the gladiatorial combats. . . .
With Constantine, the Roman Empire became officially a desacrificial polity. If he did not entirely expunge sacrifice, Constantine displaced sacrifice from the center of Roman life, pushed it to the margins and into dark corners. . . . He took away the smokey food of the not-gods (Galatians 4:8), and the demons began to atrophy. (Leithart, p. 327f)
Might as well criticise a child for not being an adult.