If memory serves, it was during the Eisenhower administration, and a lot of folks thought it had a kind of smug, self-righteous ring to it; but said: " Aw, what the heck ! If it makes people happy, why not ? "
In those dark ages, before the "one nation" phrase was added,church/synagogue attendance was exceptionally high,patriotism, the doing of good deeds, etc. was fairly normal, and we were, in some respects, a little closer to being the sort of society many of you dream we could have again.
In my humble opinion, if we are not "one nation", and at least willing to pretend we are under a watchful divine eye,saying we are, during the Pledge of Allegiance isn't going to make it happen; any more than slapping a coat of whitewash on a tomb makes a graveyard a nice place to be.