Last spring when Dr. Leithart was teaching on "Constantine and Constantinianism," he put up a number of quotes from early Church Fathers such as Tertullian and Irenaeus, which were propounding remarkably pro-Empire positions. The principle point was to show that, historically, the "Constantinian" way of thinking predated Constantine; but there also seemed to be some suggestion that, because we could show that even pre-Constantinian Christians thought this way, then it was a solidly Biblical way to think.
Theodor Mommsen, in his article, "Augustine and the Christian Idea of Progress" offers a more cynical reading of these pro-Rome pronouncements, showing that they stemmed from a syncretism of Biblical and pagan prophecy. Mommsen is not making a theological argument, but if he is correct, then we must certainly object theologically that these fathers were operating with a confused and poorly-developed eschatology, and didn't seem to have understood either Daniel or Revelation very well--they failed to understand that they were living after the downfall of the Fourth Monarchy, after the Messiah had begun to reign.
"Many Christians...actually hoped and prayed for the continuance of the Roman empire. This affirmative attitude grew out of certain historical and eschatological ideas which went back to both pagan and Jewish traditions. In the Hellenistic era there had developed in the East a theory which saw history take its course in a sequence of great, or, rather, universal monarchies. Four of these empires were to follow one another, and the series was to conclude with a fifth monarchy which, it was believed, would last to the end of the world. This idea of the four or five monarchies was adopted by some of the Roman and Greek historians, and it appeared likewise in Jewish literature. For the great image seen in a dream by Nebuchadnezzar and the four beasts seen by Daniel himself were explained by the pre-Christian tradition in terms of an interpretation of world history: these visions were believed to signify symbolically that history takes its course through the succession of four universal monarchies; the disintegration of the last of the four empires was assumed to usher in the end of the world.
In the latter part of the second century and in the first part of the third century Christian theologians like Irenaeus of Lyons, Tertulllian and Hippolytus adopted these pagan and Jewish traditions and expressed their opinion that the Roman empire 'which now rules' should be considered to be the fourth monarchy. All these Christian authors shared the belief that the fall of the last empire would be a most ominous event. Thus, Tertullian said in his treatise On The Resurrection of the Flesh (ch. 24) in which he interpreted a passage in St. Paul's 2nd Thessalonians (2:7) that the Antichrist will appear after the Roman state has been scattered into ten kingdoms. On the basis of this eschatological belief Tertullian declared very emphatically in his Apology (ch. 32.1): "There is another and greater necessity for our praying in behalf of the emperors and the whole status of the empire and Roman affairs. For we know that only the continued existence of the Roman Empire retards the mighty power which threatens the whole earth, and postpones the very end of this world with its menace of horrible afflictions." In the early fourth century Lactantius stated even more explicitly in his Divine Institutions (7.25, 6-8): "The fall and the ruin of the world will shortly take place, although it seems that nothing of that kind is to be feared so long as the city of Rome stands intact. But when the capital of the world has fallen . . . who can doubt that the end will have arrived for the affairs of men and the whole world? It is that city which still sustains all things. And the God of heaven is to be entreated by us and implored--if indeed His laws and decrees can be delayed--lest sooner than we think that detestable tyrant should come who will undertake so great a deed and tear out that eye by the destruction of which the world itself is about to fall."
To be entirely fair, though, I should say that Mommsen gets Augustine pretty atrociously wrong at points later on in this article, so it is possible that he has misrepresented Tertullian, Lactantius, et. al., though those quotes speak for themselves to a degree.