Undoubtedly, Christianity was the shared moral values needed to dominate and defend from other cultures at that time.
That being said, for whatever reason, Christianity has stopped being necessary for average person. To a certain degree, shared morality comes from books and tv shows, knowledge comes from our understanding of science.
I don't know enough to determine whether this is good or bad, but I can say that at its current state, Christianity doesn't seem to be the thing that will save white people and strengthen our ethnic identity.
It seems to me that all a return to Christianity would do is revive a highly religious, multi-ethnic society much like the ones we see in the middle east.