When did the Roman Empire fall (your thoughts)?

[Theodosius the Great]

But as Robert also noted, the material wealth was channeled into the Church rather than the civitas. Not only that, but the best of influential men entered the Church instead of the military.

On the first point I think the amount of wealth being channeled isn't as large as you may think. I see material wealth being channeled from pagan temples to churches. A famous example is the Basilica of Maxentius in Rome. Whereas, Constantine built Old Saint Peter's Basilica on Vatican Hill. So, money goes from one pocket into another pocket. But later there was also much renovating of pagan temples into churches (a much cheaper option).

Not only that, but the best of influential men entered the Church instead of the military. Our prime example was Ambrosius, the man whom Theodosius lay prostrate to.

This is a valid point, however, I don't think we can attribute this change to Christianity. The influential (i.e. Senatorial classes) where disenfranchised from holding top military posts by Septimius Severus. He replaced all the legionary legates with equestrians.

He was placed in Milan to oust the then present Arian bishop, and even the royal family couldn't change the course of events. Ambrosius was backed by a mob which even occupied the church like a 1960's "sit-in." It's very hard to view the West of the mid 4th century as not actively and popularly Catholic. Paganism was "mostly dead but not totally dead," to quote Billy Crystal.

Milan was probably the most Christian city in all Italy. Hence, Ambrosius wielded more influence than the Pope in still-pagan Rome. Paganism was dominant in the Senatorial classes of the entire fourth century and into the early fifth century. The rustics in the country side in all the provinces were mostly pagans (the word "pagan" means "country-dweller"). And Italy was probably the most pagan province in the West. The center of Latin Christianity was the province of Africa. Western Europe was the most pagan area of the entire empire.

The crux of the matter appears as a slow decline in patriotism

Our concept of patriotism is a modern one. In ancient times it was more a matter of loyalty to one's own city.

What you are saying makes sense, and I’m unable to argue against it, but I keep thinking this is inadequate and we are missing something. The Roman state was practically defined by its openness to foreigners.

I think Alanus is on to something. When facing a superior (or near-superior) enemy this openness to outsiders fell by the wayside. For example, I can't imagine the Romans being so open to a Carthaginian between any of the Punic Wars. Or a Persian/Parthian during the empire. Manicheans were targeted by Diocletian because he saw them as a potential Persian fifth column.

So, I do see a religious component in the change of attitude. On the one hand, I think Christianity reenforced or even liberalized the traditional Roman attitude towards foreigners. Barbarians became fellow Christians. OTOH, this might not be the case if the foreigners in question were heretics which was probably the worst thing they could be. The Goths were an exception, of course.

The army recovered long before Dacia was abandoned by Aurelian, or, it was in back in good shape by then.

Possibly. I suspect this recovery came at the expense of denuding the troops of Dacia though.

It certainly helped that the east was richer and spared the bulk of barbarian attempts at permanent settlement i.e. luck played a role.

I'm not sure I agree. The Visigoths in the fifth century roamed in both the western and eastern provinces. (Remember, Stilicho was condemned for chasing Alaric into the East). I think Vandals may have invaded from the East like the Visigoths as well. Of course, Britain was invaded by the Saxons, et al.

In addition, both the eastern and western provinces were hammered by Attila about equally. Although, I don't think he ever attempted to settle onto Roman ground.

Also, the East was richer as you said, but until 394 A.D. the West had the superior field army due to Adrianople. And it had two incontiguous borders to defend - the Euphrates and Danube - which in the long run were more difficult to manage than the Western frontier, IMO.

I doubt the barbarians actually went to church, especially if they were aryan and despised catholic churches in their midst. And as mostly illiterates I doubt there was much religious instruction.

I agree with Marja. I don't believe the migratory nature of the barbarians prevented them from internalizing Christianity at all since they had their own Arian clergy. And most Romans were always illiterate. High literacy rates is a very modern phenomenon, AFAIK.

~Theo