Although I get, and agree, with your main point (the demise of America and the exultation of a sinful and depraved culture), I believe there were quite a few Christians in the Roman Army.
In the writings of Justin Martyr, there is a letter supposedly written by the Emperor Marcus Aurelius - who had launched many persecutions against Christians. He was stuck out in the middle of nowhere, surrounded angry Germanic (I repeat myself) tribes, and after his prayers to his gods had failed, he asked if there were any Christians amongst his troops so they could pray for help from their God. He was shocked (and 'irritated'), that there were many Christians amongst their numbers ... but when their prayers were answered, he put an end (albeit, only temporary) to the persecutions.
Below follows a copy of this letter which is just after Justin Martyr's First Apology, as contained in The Ante-Nicene Fathers, vol. I.
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The Emperor Caesar Marcus Aurelius Antoninus, Germanicus, Parthicus, Sarmaticus, to the People of Rome, and to the sacred Senate, greeting!
I explained my plan to you and what advantages I had gained on the borders of Germany after much labor and suffering. Due to the circumstances of this war, I was surrounded by the enemy in Carnuntum. 74 cohorts cut us off from help, being stationed 9 miles off.
Then the scouts pointed out to us that the enemy was at hand. Our general, Pompeianus showed us that a mixed multitude of 977,000 men was closing in on us, which we all could see. I was cut off by this vast host, and I had with me only a battalion composed of the first, tenth, double, and marine legions.
I examined my own position and my army, considered the vast mass of the barbarian enemy, and I quickly betook myself to prayer to the gods of my country. They disregarded me.
So I summoned those among us who go by the name of Christians. After some inquiry, I determined that there was a great number and vast host of them. When they appeared before me, I raged against them.
This was not appropriate, for afterwards I learned their power.
They began the battle not by preparing weapons or bugles. Such preparation is hateful to them because of the God they carry around in their conscience. We call them atheists, but it seems that they have a God as their ruling power in their conscience. I say this because they threw themselves on the ground and prayed not only for me, but for the whole army as it stood, so that they might be delivered from the present thirst and famine. For five days we had gotten no water because there was none. We were in the heart of Germany and in the enemy's territory.
As soon as they threw themselves on the ground and began praying to God—a God of whom I am ignorant—water poured from heaven. On us it was most refreshing and cool, but upon the enemies of Rome it was a withering hail.
We also immediately recognized the presence of a God after their prayer, a God unconquerable and indestructible.
Because of this, then, let us pardon such as are Christians, lest they pray for and obtain such a weapon against us! And I counsel that no such person be accused by our courts only on the ground of being a Christian.
If anyone is found laying to the charge of a Christian that he is a Christian, I desire that it be made clear that he who is accused is a Christian. If he acknowledges that he is one and is accused of nothing else, then whoever arraigns him should be burned alive.
I also desire that whoever is entrusted with the government of the province shall not compel the Christian, who confesses and certifies such a matter, to retract.
These things should be confirmed by a decree of the Senate.
I command that this my edict be published in the Forum of Trajan in order that it may be read. The prefect Vitrasius Pollio will also see that it is transmitted to all the provinces round about.
The oaths to the Emperor as a god, were a pro-forma ceremony, consisting of throwing some insense on a fire—usually as a unit. Of course some would get away with mumbling “Jesus is Lord” (instead of the required “Ceasar is Lord”...where the “Jesus is Lord” phrase originated) under their breaths or staying silent...so yes, Christians were in the Roman army.
The Romans by pagan standards were not intolerant at all—as to a poly-theist, swearing to (yet) another god is no big deal. Of course to a monotheist Christian or Jew things were entirely different.
Most of the known Christian Roman soldiers (and certainly in Justin’s day) were new CONVERTS however, ex pagans—who often suffered severe persecution and even death, if their faith became known.
Since Christianity gained its biggest foothold in the lower classes—where most soldiers then (and now) came from—naturally lots of soldiers became Christians—coming out of paganism.
Noteably, John the Baptist when asked about it, didn’t require soldiers to resign before baptism—rather that they were not to extort civilians—and were to be content with their (low) pay. So Anabaptist pacifist Christians (like Mennonites or Quakers) are incorrect to identify a commitment to pacifism a requirement of the earliest Church—it was all about refusing to worship the Emperor that pushed Christians away from the Roman military.