Gandalf Vs. The Witch King

As I mentioned in another thread, I think Erik Tracy has explained Tolkein's work in a balanced way, & in a good context. It may well be speculation to some extent, but very promising nonetheless. Balrogs afterall were the servants of Morgoth, not Sauron; they did not have a great part of their original strength taken away from them like Sauron did either. In the LOTR Sauron did not even try to acquire the Balrog for aid. In terms of commanding will, why would a Balrog submit to Sauron given the circumstances of power each has? A strong case could be made that the Balrog could even rival Sauron in combat, irrespective of whether it lost.