All of this is to say: Michael Horton needs to stop being “baffled” at these characterizations of the Two Kingdoms paradigm. They are taught explicitly and emphatically in the very book he is recommending. Having spent a good deal of time carefully reading VanDrunen’s book, Tim Keller’s generalizations (the immediate source of Horton’s ire) strike me as perfectly reasonable and fair.
In my carefully considered opinion, David VanDrunen argues for an almost complete dualistic split between heavenly and earthly callings. If Horton wants to put Humpty Dumpty back together again and view them as unified and complimentary, I suggest he walk down the hall and have a nice, long visit with his colleague. Because from the looks of Horton’s blog post, the right hand at WSCAL doesn’t know what the left hand is doing.