If, as Yoder claims, the “Constantinian” compromise of the church with the world begins in the second and third centuries; if it begins when Christianity is still an illicit religion, persecuted periodically but savagely; if it begins when the church is still populated by martyrs – is it still a Constantinian shift? That is, is the shift attributable to the church becoming legal, official, the majority religion, the religion of the empire?
Evidently not. Whatever shift there was in the second and third centuries, it has other sources and is evidence (as Gerald Schlabach has suggested) of more general problems of Christian faithfulness rather of the mainstreaming of the church.
Yoder’s acknowledgement that the church was becoming Constantinian before Constantine is not a qualification of his thesis. It undermines his thesis.