That’s damn close. 
I’m late to the thread but I remember reading Dialogues with the Devil (Taylor Caldwell?) many years ago. The theory in the book, IIRC, was that Satan believed that humans were beneath god and were unfit to be in heaven with the angels and the big guy. He believed this so much that he pissed off the boss and was kicked out for his never-ending quest to prove his point by inducing humans to do things that excluded them from paradise. Or something like that.
They could just as easily be doing God’s work as the devil’s. I would suggest that Gandhi was unwittingly working for God even though he didn’t believe in him. Hitler was supposed to be a Christian, I would suggest he was doing the devil’s work.
Hitler’s ideas about Christianity were just plain nutty (quelle surprise). He believed that Jesus was an Aryan and hated the Jews. After Christ’s death at the hands of those evil Jews, Paul, a scheming Jew, took over Christianity and perverted the pure Aryan teachings of Jesus to forge a weapon to bring down the noble Roman Empire. See Hitler’s Table Talk for more loony toon stuff from the Fuhrer.
But he threw in this uniform with admiral’s stripes and shiny buttons and everything!
OK, seriously though. With the caveat that I’m no theologian, I think the underlying premise is that human beings have free will, so each of us has to decide which way we wish to go–either accept divine grace and forgiveness of sin, or go the way of the devil. So it becomes a gigantic sales competition between God and Satan that may even exceed the intensity of rival soft drink companies.
I was telling one of my co-workers about this earlier this morning: back in the early '80s there was this music video for this song called “Le Diable.” Not surprisingly it was sung in French. Maybe a little surprisingly it was sung by some guy from South America (but not from a country where French is the official language). Anyway, the gist of the song is that “le diable” comes back to earth after his 1000 years of exile (or whatever. I’m not much into all of that religious stuff) to terrorize humanity only to discover that we humans are doing a fine job of mucking everything up without his help. I’d say the song was pretty much spot on.