Lewis is writing as “Uncle Screwtape”, a veteran demon who is tutoring his nephew in the art of temptation. This being the case, God is referred to as “the Enemy”.
About the general connection between Christianity and politics, our position is more delicate. Certainly we do not want meant to allow their Christianity to flow over into their political life, for the establishment of anything like a really just society would be a major disaster. On the other hand we do want, and want very much, to make men treat Christianity as a means; preferably, of course, as a means to their own advancement, but, failing that, as a means to anything—even to social justice. The thing to do is to get a man at first to value social justice as a thing which the Enemy demands, and then work him on to the stage at which he values Christianity because it may produce social justice. For the Enemy will not be used as a convenience. Men or nations who think they can revive Faith in order to make a good society might just as well think they can use the stairs of Heaven as a short cut to the nearest chemist’s shop. Fortunately it is quite easy to coax humans round this little corner. Only today I have found a passage in a Christian writer where he recommends his own version of Christianity on the ground that ‘only such a faith can outlast the death of old cultures and the birth of new civilisations.’ You see the little rift. ‘Believe this, not because it is true, but for some other reason.’ That’s the game.
Your affectionate uncle
C.S. Lewis, The Screwtape Letters, p. 126-7